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Katie Meyers
Topic One Compendium Review
Note: I began this topic by reading the book chapters and then viewing the PowerPoint presentation. As a result, I have mentally organized this information based on the book. This compendium review’s organization will be loosely based on the book chapters. Also, as reviews are more beneficial for me in outline form, that is how I constructed this compendium review.
Table of Contents:
Exploring Life and Science
- Life
- Definition (characteristics) of life
- Hierarchy of life
- Human classification – biological and cultural
- Science
- Scientific Theories
- Scientific Method
- Scientific Studies
- Science and Technology
Chemistry of Life
- Matter
- Element
- Atom
- H2O
- Solutions – pH scale
- Buffers
- Biochemistry – carbohydrates, proteins, fats/lipids, DNA/RNA
Cell Structure and Functions
- Cell size
- Cell type – prokaryotic, eukaryotic
- Plasma membrane
- Endomembrane system
- Cilia and Flagella
- Mitochondria
Organization and Regulation of Body Systems
- Tissues
- Cell junctions
- Skin
- Organ systems
- Body cavities
- Body membranes
- Homeostasis
- Positive feedback
- Exploring Life and Science – Life
· Definition (characteristics) of life
o Energy – necessary to maintain organization of a cell and/or organism; converted to motion by most living things
§ Life cannot continue without outside materials/energy; humans and animals acquire it by eating food
· Food provides nutrient molecules, which are the building blocks for energy
o Reproduction – fundamental of life; consists of creating a copy of oneself by use of DNA replication
§ Allows cells and organisms to reproduce
§ Holds hereditary info that directs cell structure and metabolism (all the chemical reactions in a cell)
o Growing and developing – life continually changes from fertilization to death; consists of all the stages of life, as well as any repairs made during life; all organisms undergo development
o Homeostasis – an internal environment that varies within narrow limits, or maintaining a stable condition; all body systems help maintain it
§ E.g. – homeostasis systems in humans: digestive, respiratory, cardiovascular, metabolic, urinary, nervous, endocrine
o Response to stimuli – living things respond with movement to external stimuli; homeostasis made possible only by internal and external response to stimuli
§ Movement type differs depending on nervous and musculoskeletal systems
§ Movement constitutes a large part of an animal’s behavior
o Organization from evolution – a process by which a species changes through time; explains unity and diversity of life
§ Adaptation – a new, stronger evolutionary variation gradually becomes the majority due to its superiority
· Hierarchy of life (smallest to largest) – Can be explained by evolution (which continues today)
o Atom
o Molecule – made up of atoms
o Cell – made up of molecules; smallest structural and functional unit of life
§ E.g. Skin: made of two types of cells
o Tissue – group of similar cells that perform a particular function, e.g. nerve tissue
§ E.g. Skin: cells make up skin tissues
o Organ – made of several types of tissues
§ Each organ belongs to an organ system
§ E.g. Skin: tissues make up skin organ
o Organ System – a group of organs working together to accomplish a common purpose
§ E.g. Skin: part of integumentary organ system
o Organism – a collection of organ systems
§ E.g. Skin: part of human body
o (Species) – a group of interbreeding organisms
o Population – all species in a particular area
o Community – various populations in the same area
§ E.g. humans interact with the rest of their community
o Ecosystem – a community of populations that interacts with it’s physical environment
§ E.g. humans interact with the rest of their ecosystem
o Biosphere – all of Earth’s ecosystems
· Visual aid for the hierarchy of life
· (from slide 5 of BIO 156 – Cells PowerPoint presentation)
· Humans imbedded in natural world
· Living things classified into three domains: Eukarya (have membrane-bound nucleus), Archaea, and Bacteria (latter two lack membrane-bound nucleus)
o Eukarya domain houses four kingdoms: Animalia (animals, e.g. worm, bird, human), Plantae (plants, e.g. tree, fern, moss), Fungi (fungi, e.g. black bread mold, yeast, mushroom, fungus), Protista (protists, e.g. paramecium, euglenoid, slime mold, dinoflagellate)
§ Animalia kingdom – houses vertebrate creatures (vertebrate: a nerve cord protected by vertebral column, evidenced as “segmented animals”)
· Mammal vertebrates have hair and mammary glands
· Human classification: mammal vertebrates of the Animalia kingdom in the Eukarya domain
· Are humans directly descended from apes? No. Humans and apes are cousins; in other words, they descended from the same “ape-like” ancestor.
o Distinctive human features (features apes do not have): highly developed brains, completely upright stance, creative language, ability to use wide variety of tools
§ Only humans have symbolical communication (language), learned by instruction and imitation
· Apart from biological heritage (see above), humans also have cultural heritage
o Culture – human activities and products passed from generation to generation outside of direct biological inheritance
· The more civilized a human culture is, the more we think we are not part of nature. However, humans are dependent on the environment and a part of the biosphere. The human population alters and therefore threatens the biosphere, resulting in reduced biodiversity and extinction.
o Extinction: the death of a species are larger group of organisms; estimated extinction of 400 species per day
o Bioethical issue of preserving our biosphere and biodiversity, as it will result in the ability for humans to continue existing due to our dependency on them.
Exploring Life and Science – Science
· Science…
o Is a process
o Is a way of knowing about the natural world
o Strives for objectivity
· Scientific theories – concepts about the order and patterns in the natural world or the natural world’s organization, based on a wide range of observations and experiments, e.g. the discovery of the cause of ulcers and how to treat them
o E.g. theories and their concepts
§ Cell – all organisms are made up of cells, new cells only come from pre-existing cells
§ Homeostasis – internal environment of an organism stays relatively constant
§ Genes – organisms contain coded info that dictates their form, function, and behavior
§ Ecosystem – population of organisms interact with each other and the physical environment
§ Evolution – all things have common ancestor, but each is adapted to a particular way of life
· Evolution is the unifying concept of biology; it is a principle (meaning it is widely accepted)
· Scientific method – has steps: initial observation, date, hypothesis, experiment/observe, conclusion, scientific theory
o Data – facts pertinent to the matter at hand
o Hypothesis – formed with imagination and creative thinking; becomes the basis for more observation/experiments; subject to change; cannot be proven true but can be proven untrue
o Conclusion – does or does not support hypothesis
· Here is a chart of how the scientific method works
(found at http://courses.unt.edu/hwilliams/GEOG_1710/science.htm)
· Controlled study – an experiment with a series of procedures to test a hypothesis
o Attempt to keep everything the same except for the different medications being tested; reduce variables like sex and weight
o Controlled group and test group(s) – first is not given any medication, to see if the medication given to the test group(s) has an effect
§ All groups take something and are under the impression they are taking the medication in question so none of the test subjects can have thoughts to influence the medication’s effect
o When neither patient nor examiner is aware of who gets what pill, it is called a double-blind study.
· Scientific studies are later published in scientific journals for availability to the science community
o If an experiment is poorly done or questionable, the journals can reject it.
o The primary author of a study is usually the researcher who performed the study.
o If looking online, look for studies at websites with the suffix .edu, .gov, or .org for reliable info
· Years of experimenting are necessary for a scientific study/hypothesis to be considered well founded by the science community.
· When making sense of a scientific study, look at…
o Type of data given to support the study; anecdotal data (individual testimonies) are considered unreliable
o Keep in mind that not all correlations (relationships, two things occurring at the same time) turn out to be causations (one thing is causing the other).
o Instead of jumping to the conclusion, examine the researcher’s methodology (tells how study was conducted) and results (tell what facts [data] were discovered, the conclusion and data are not the same)
o Ask yourself if the conclusion is justified by the data
o Good summary of data: bar or line graph
o Standard error – tells how uncertain a particular value is; .1% is recommended before taking a medication
· Science and technology – science is the driving force behind technology
o Technology – the application of scientific knowledge to the interest of humans
o Biotechnology – has benefits and risks; one concern is genetic modification (GM)
o Scientific investigation and technology are always affected by human values; all citizens should be fully informed so they can make educated value judgements
o Ethical issues: clone therapy, modification of a person’s genetic inheritance, stem cell research, maintaining human lifestyle vs. wildlife communities
Chemistry of Life
· Matter – anything that takes up space and has mass; can exist as a solid, liquid, or gas
· Element
o each has a name and symbol (e.g. carbon = C, iron = Fe, sodium = Na)
o a basic building block of matter
o cannot be broken down by chemical means
o 92 naturally occurring elements
o over 90% of human composition is of four elements – carbon, nitrogen, oxygen, hydrogen; others are vital to human health (like iron)
· Atom
o smallest unit of an element that still retains chemical and physical properties of the element
o same name is given to the element and its atoms
o each has central nucleus and pathways about nucleus called shells
o contains subatomic particles called protons (+ charge, one atomic mass) and neutrons (no charge, one atomic mass) in the nucleus and electrons (- charge, no atomic mass) orbit nucleus in shells
o mostly empty space
o atoms make up an unnumbered element only when they have a neutral charge
· Joining atoms: 2 bonds – ionic bond, covalent bond
o Ionic bond – atoms give up or take on electrons to achieve a stable outer shell
o Covalent bond – atoms share electrons
§ Single bond – atoms share one pair of electrons
§ Double bond – atoms share two pairs of electrons
§ Triple bond – atoms share three pairs of electrons
· H2O makes up 60%-70% of human body weight
· H2O has…
o polar molecules – when a larger atom has greater ability to attract electrons than smaller atoms do; attracted more to oxygen, the oxygen element slightly negative and the hydrogen elements slightly positive
o hydrogen bonds – when a covalently bonded hydrogen is slightly positive and is attracted to a negatively charged atom a ways away; relatively weak, can be broken easily
o These two water qualities keep it as a liquid at room temperature, as well as change its temperature slowly, making it a good temperature buffer
o Because H2O molecules are cohesive, water is an excellent transport medium
· Two types of solutions – acidic and basic
o Acidic – high positive hydrogen concentration, e.g. lemon juice, vinegar, tomatoes, coffee; dissociate in water, releasing hydrogen ions; if dissociation is complete/near complete, it is considered a strong acid
o Basic – low positive hydrogen concentration, e.g. ammonia
· pH scale – indicates acidity/basicity (alkalinity) of a solution
o Pure water = 7
o Very acidic = 0
o Very basic = 14
· Buffers – present in the environment to prevent large pH changes, as such large changes are bad for humans
o Acid rain/snow is caused by overwhelmed buffers from gasoline burning; kills fish, forests, decomposes statues
· Organic molecules in cells are composed of subunits; macromolecules contain many subunits (macromolecule subunits separate after adding H2O to them)
· Biochemistry: study of the (organic) Carbon-chain Molecules of Life (see below)
(from slide 8 of BIO 156 – Cells PowerPoint presentation)
o Carbohydrates
§ Composed of simple sugars (monosaccharide) – common ones are glucose, fructose, galactose (in milk)
§ Stores energy in complex form
§ Broken down into simple energy for use in cell metabolism in mitochondria
§ Quick and short-term energy storage in all organisms
o Proteins
§ Protein is macromolecule with amino acid subunits
§ Primary importance in structure and function of cells
§ Protein structure – 3-4 levels
· Primary structure – linear sequence of amino acids joined by peptide bonds; each polypeptide has its own sequence of amino acids
· Secondary structure – polypeptide takes certain orientation in space, alpha helix or beta (pleated) sheet
· Tertiary structure – final 3-D shape, created by covalent, ionic, and hydrogen bonding
· Quaternary structure – e.g. hemoglobin, many enzymes
§ Support – keratin (hair and nails), collagen (ligaments, tendons, skin) are structural proteins
§ Enzymes – speed chemical reaction in cells, specific to type of reaction, function at room temperature
§ Transport – channel and carrier protein in plasma membrane, allows entrance and exit to cells; hemoglobin transports oxygen in red blood cells
§ Defense – antibodies are proteins, combine with antigens so antigens don’t destroy cells and upset homeostasis
§ Hormones – regulatory proteins, intercellular messengers that influence cell metabolism, e.g. insulin and growth hormones
§ Motion – contractile proteins actin and myosin cause muscles to contract at cellular level
§ Amino acids – subunits of protein
§ Made complex by amino acid chains folding for protein’s specific job
· Very complex, each chain made of thousands of amino acids
· Specific shapes allow specific chemical reactions to happen
· How do proteins fold? This remains unanswered.
§ Stores DNA that runs a cell’s metabolism
§ Protein folding
· Folds into different shapes for specific functions
· Misfolding and aggregation (clumping) can lead to diseases like Alzheimer’s, Mad Cow disease, Parkinson’s, and cancer
o Mad Cow disease caused by aggregation in the brain
o Alzheimer’s is caused by aggregation of 42 amino acid proteins called Abeta peptides. These small aggregation clumps are toxic to neurons and cause neuron cell death, which is the reason for the neurodegenerative consequences.
o How can we treat or cure these diseases? As protein folding is still a bit of a mystery to mankind, we do not have the answer to this question as of yet. However, extensive research into learning more about protein folding (and how to prevent such diseases) is being done across the world. For such an example, visit http://folding.stanford.edu/index.html. Also, there is a super-computer project called IBM-Blue Gene that is dedicated to figuring out the foldings and misfoldings of protein.
o Fats/Lipids
§ Bodily functions – long term energy storage, insulates against heat loss, protective cushion around major organs
§ Contain more energy per gram than other biological molecules
§ Stored in animal fats and plant oils (ideal for energy storage molecules)
§ Lipid fats – lard, butter (animal origin); solid at room temperature
§ Lipid oils – corn oil, soybean oil (plant origin); liquid at room temperature
§ Long-term fat storage is unique in mammals
§ Form much of the plasma membrane on cells – separates interior of cells from their surroundings
§ Steroids – large lipid class including sex hormones; anabolic steroids (for muscle-building) illegal because of harmful side effects
§ Fatty acid – carbon-hydrogen chain that ends with acidic group COOH; comes either saturated or unsaturated
· Saturated – no double carbon bonds, solid at room temperature; cause plaque in blood vessels (can lead to heart disease)
· Unsaturated – double carbon bonds, liquid at room temperature
o Monounsaturated and polyunsaturated found to protect against heart disease
§ Trans fats – made from partial hydrogenation; more harmful than saturated fats; found in processed foods and margarine
o DNA/RNA (Nucleic Acids)
§ Store and use info
§ Both are polymers of nucleotides
§ Made of nucleotides (or “bases”) called A (adenine), C (cytosine), G (guanine), T (thymine) (DNA only), U (uracil) (RNA only)
· A and G have two rings each, T and C have one each
§ One DNA strand can be millions of nucleotides long
§ DNA
· stores genetic info in cell and organism
· duplicates to pass on genetic info
· two strands held together by hydrogen bonds between bases, resembles twisted stepladder
o sides of ladder made of phosphate and sugar molecules, rungs made of complementary paired bases (T – A, G – C)
§ Complementary paired bases have shapes that fit together
o Sequence of bases determines sequence of amino acid in protein
· faulty DNA results in illness, e.g. sickle cell
· Sugar content called deoxyribose
§ “Messenger” RNA
· Transmits DNA’s instructions regarding amino acid sequence in protein
· Single stranded
· Complementary base pairs with one DNA strand – passes correct sequence of bases to RNA
· Sugar content called ribose
§ ATP – adenosine triphosphate
· Energy carrier – muscle contractions and nerve impulses
· Input of energy required to reform ATP from ADP + P
· Glucose breakdown leads to ATP build-up, convert glucose to ATP for usable energy in cells (chemical reaction)
o Oxygen is part of glucose breakdown – lack of oxygen leads to lack of energy
· Biochemical pathways – convert substrate molecules into specific products needed by body
o Two fundamental types
§ Anabolic – building a complex from less complex substrates
§ Catabolic – breaking down a complex molecule to make energy available for biological processes
Cell Structure and Functions
· Cell complexity equivalent to visible world (e.g. a city) complexity
· Fundamental unit of life – the first level where one can understand the basic characteristics of life – lowest hierarchal level where life truly exists
· First life was cellular, as evidenced by rocks
· Molecules of life (the basics of life) make up cells
· Hemoglobins – transport oxygen to cells, very important
· Cells differ in looks from one another; specialized (in multicellular creatures) in structure and function
· Cell size – e.g. hen or frog egg, however most invisible to naked eye
o The smaller the cell, the better – less distance to travel internally
· Two types of cells
o First to exist was the prokaryotic cell
§ Relatively simple and small
§ Has cytoplasm – matrix is semifluid medium which contains H2O and other molecules suspended or dissolved in medium
§ Has no organelles containing the “Molecules of Life” in cytoplasm
§ Each has a…
· Cell membrane – outer membrane that registers what enters and exits a cell, selectively permeable due to embedded proteins; primarily made up of a phospholipid bilayer; marks boundary between outside and inside of cell
· DNA molecule loose in cytoplasm (no nucleus, or membrane-enclosed structure where DNA would be found)
· Small ribosomes
o Proteins are assembled here from DNA info
· Flagella and/or cilia
§ An example of a prokaryotic cell is bacteria
(from slide 15 of BIO 156 – Cells PowerPoint presentation)
o Eukaryotic cell
§ Came much later than prokaryotic cells – evolved from prokaryotic cells, actually
· (From http://nsw.royalsoc.org.au/journal/campbell.html)
· The above image shows endosymbiotic joining of the original prokaryotic cell with other prokaryotic cell parts, resulting in the eukaryotic cell. These prokaryotic cell parts became what we now know as the mitochondria and chloroplasts in today’s eukaryotic cells. Mitochondria and chloroplasts have their own DNA, separate from the rest of their eukaryotic cell, as well as share most of the features of a prokaryotic cell. Such information suggests that today’s mitochondria and chloroplasts were once their own (or at least a part of a) separate cell, a prokaryotic cell, thereby reinforcing evolution.
§ More complicated and much bigger than prokaryotic cells (at least 100X bigger)
§ Has membrane-bound organelles
§ Plants and animals are made up of these cells
· A eukaryotic cell is made up of…(a summary; further details about parts and how they work are found below)
o A cell (plasma) membrane (a phospholipid bilayer) (like a prokaryotic cell)
§ H2O and noncharged molecules are allowed through the membrane
§ Proteins in plasma membrane help select molecules pass in/out like macromolecules and charged molecules.
§ Carbohydrates attached to proteins and lipids
§ Separates cell from surroundings—in other words, it helps cell be homeostatic
§ Contains supporting cholesterol
o A nucleus
§ Holds DNA/RNA and related chromatin, a type of protein – holds genetic info
· Each cell has same genes, DNA turns certain ones on or off, depending on cell’s function
· DNA/RNA specify protein’s functions in a cell
§ Bound by porous nuclear envelope
§ Includes nucleoplasm – different composition from cytoplasm
· Contains chromatin, which coils into chromosomes just before cell divides
o Chromosome – contains DNA molecules and associated proteins
§ Nucleolus – where ribosomal RNA is produced and where rRNA joins with protein to form subunits of ribosomes
o Mitochondria (provide simple sugar) and/or chloroplasts—energy
§ Made up of tiny organelles of RNA and protein
o A cytoskeleton: internal membranes that organize a cell’s spaces and distribution of the “Molecules of Life” – help organize, in short
§ Made of protein fibers that crisscross cytoplasm
§ Helps maintain cell’s shape
§ Anchors and assists movement in organelles
§ Contains microtubules – larger than actin filaments; cylinder that contains 13 rows of tubulin (type of protein)
o Nuclear envelope: surrounds nucleus; has nuclear pores that permit passage of ribosomal subunits out of nucleus and protein into nucleus
o An endoplasmic reticulum (ER):
§ Rough ER (has ribosomes) and smooth ER (has no ribosomes)
§ Found in nuclear envelope around nucleus
§ A membrane system of saccules and channels
o Centrioles and centrosome: both made up of microtubules
o Lysosomes: transport molecules around the cell—are either empty or full
o Golgi apparatus: packages molecules
o Has cytoplasm – matrix is semifluid medium which contains H2O and other molecules suspended or dissolved in medium
§ Cytoplasm contains organelles, small structures that perform different functions
· For the much-needed visual aid, here is a diagram of a eukaryotic cell
(from http://www.ebi.ac.uk/microarray/biology_intro.html)
§ Here is a diagram neatly stating what eukaryotic cells do
(from slide 20 of BIO 156 – Cells PowerPoint presentation)
· 5 ways things move across the plasma membrane
o Diffusion – “random movement of molecules from a higher concentration to a lower concentration (e.g. smoke)” (slide 27 of BIO 156 – Cells PowerPoint presentation) until equally distributed – no cell energy needed
o Osmosis – like diffusion, except specific to water molecules (tonicity)
§ Tonicity and how it changes a cell
· Isotonic solutions have the same water/salt solution on the inside and outside of a cell; no H2O exchanging done, cell remains the same size
· Hypotonic solutions have more salt on the inside of the cell than on the outside; H2O is absorbed into the cell in an attempt to equalize the solutions, cell becomes bloated and may burst
· Hypertonic solutions have more salt on the outside of the cell than on the inside; H2O is sucked out of the cell in an attempt to equalize the solutions, cell shrivels
o Facilitated transport (or facilitated diffusion) – transport of molecules through the protein “tunnels” in the plasma membrane, according to how diffusion works: from higher concentration to lower concentration; requires no energy (ATP)
o Active transport – transports molecules through protein “gateways” like facilitated transport does, except it goes against diffusion and transfers molecules from lower concentration to higher concentration; requires energy (ATP)
§ Sodium/potassium pump ideal example
o Endocytosis and exocytosis
§ Endocytosis – transports molecules (e.g. neurotransmitters, hormones) into the cell by pinching the plasma membrane around said molecules until it becomes a vesicle that can move about the cell holding those molecules
· Phagocytosis – white blood cells pick up pathogens by endocytosis
· Pinocytosis – picking up molecules and fluid
§ Exocytosis – the opposite operation of endocytosis – vesicle fuses with plasma membrane and secretes contents out of cell
· Protein Synthesis
o Cellular objects required: nucleus, ribosomes, endomembrane system (organizes molecules)
· Endomembrane system – “a series of membranes in which molecules are transported in the cell” (from slide 35 of BIO 156 – Cells PowerPoint presentation)
o Is made up of: nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles
§ Rough ER – makes proteins with ribosomes studded on it
· Larger ribosomes (found on the surface of the rough ER) for assembling protein according to DNA info (distinctly different from a prokaryotic cell)
§ Smooth ER – helps make carbohydrates and lipids; lacks ribosomes
§ Golgi apparatus – processes, packages, and delivers proteins and lipids from the ER’s; looks like flattened stacks (pancakes)
§ Lysosomes – made by Golgi, contain digestive enzymes and hydrolytic enzymes, are membranous vesicles
§ Vesicles – “small membranous sacs used for transport” (from slide 37 of BIO 156 – Cells PowerPoint presentation)
o Here is a visual aid for the above system:
(from http://www.uic.edu/classes/bios/bios100/lecturesf04am/membrane_flow.jpg)
· Cilia and flagella
o Both…
§ Made of microtubules
· Special arrangement of proteins, form threadlike structure at molecular level
§ Used in movement
o Cilia 20X shorter than flagella
o One flagella attached to object (e.g. sperm); many cilia attached to object
· Mitochondria
o Look like a bacteria living in the cell; thought to have come from an engulfed prokaryotic cell earlier in evolution
o Convert chemical energy of glucose into chemical energy ATP
o Use oxygen and give off carbon dioxide in the process
o “Highly folded organelle in eukaryotic cells” (from slide 38, BIO 156 – Cells PowerPoint presentation)
o Produces ATP energy
o Cristae – made of the many folds in the interior membrane layer; makes energy, breaks down sugar into ATP
o Cellular respiration
§ Part of (and important to) cell’s metabolism
§ Produces cell’s ATP
§ 3 steps – glycolysis (2 ATP) (anaerobic), citric acid cycle (2 ATP) (releases carbon dioxide), electron transport chain (32 ATP)
§ Happens when sugar’s/glucose’s carbon bonds are broken down and energy from said carbon bonds is stored as an ATP (hi-energy phosphoric bond); after this, ATP leaves the mitochondria to be used elsewhere in the cell
§ Each reaction requires specific enzymes; no reaction occurs unless the enzyme is present
§ Glucose more common respiration/energy source; however, other molecules can be used for same means: other carbohydrates, proteins, lipids
§ Athletes have an increase in fat metabolism that keeps blood glucose at a normal level
§ This is an image of the process of cellular respiration
(found on website http://home.earthlink.net/~dayvdanls/CRespIndex.htm)
o Here is a drawing of a mitochondria:
(“Human Biology”, by Sylvia S. Mader, 10th ed. Page 52)
· Fermentation
o Occurs when cell makes ATP without using oxygen
o Happens in cytoplasm
o Involves glycolysis
o Makes only 2 ATP and lactate
o Gives humans a short burst of energy
· Overall, what does cellular metabolism do? It “runs all the reactions that make it alive…grow, reproduce, develop, move, maintain internal homeostasis, respond to stimuli.” (from slide 44 of BIO 156 – Cells PowerPoint presentation) It also involves hundreds, thousands, (a LOT), of chemical reactions. Proteins or enzymes catalyze every reaction in a cell’s metabolism. Also, every protein’s amino acid sequence is encoded in the DNA. These amino acid sequences are very complicated; super-computers from around the world continue to work and try “to figure out how, based on their unique amino acid sequence, all the different cellular proteins take on the particular shape they have, and control the particular reaction they catalyze” (from slide 46 of BIO 156 – Cells PowerPoint presentation). In the end, protein function is the key to understanding cell metabolism.
Organization and Regulation of Body Systems
· Tissue (4 types) – in layman’s terms, a bunch of cells grouped together to do the same thing and work together (or, “a collection of cells of the same type that perform a common function” [from slide 48 of BIO 156 – Cells PowerPoint presentation ]).
o Connective
§ Three main types: fibrous (loose and dense), supportive, fluid (blood, lymph)
§ Relatively few cells, mostly protein fibers with a few specialized cells and some ground substance (noncellular, can be anywhere from a solid to a fluid)
§ Together, ground substance and protein fibers make up the tissue’s matrix
§ “Binds and supports parts of the body” (from slide 53 of BIO 156 – Cells PowerPoint presentation)
§ Holds together body parts like: tendon, bone, cartilage
§ Supports: blood vessels, nerves, cell populations
§ Loose fibrous
· Supports epithelium and many internal organs (lungs, arteries, bladder, muscles, blood vessels, nerves)
· Protective covering
· Cell type of loose fibrous connective is called adipose
o Enlarged cells, store fat
o Used for energy, insulation, organ protection
o Found beneath skin, around kidneys, surface of heart
§ Dense fibrous
· Contains many collagen fibers packed together
· More specific function than loose fibrous
· Found in tendons and ligaments
§ Supportive – e.g. cartilage
· Heals slowly
· Cells lie in small chambers (lacunae) separated by solid flexible material
· Three types
o Hyaline – most common; glassy, translucent matrix – e.g. nose
o Elastic – more elastic fibers than hyaline; more flexible – e.g. outer ear
o Fibro – strong collagen fiber in material; withstands tension and pressure – e.g. wedges in the knee joint
§ Bone
· Most rigid; hard matrix of inorganic salts (calcium salts) and protein fibers (collagen fibers)
· Compact bone
o Cylindrical structure units called osteons, in which are canaliculi and the central canal
· Spongy bone
o At the ends of long bones
o Open bony latticework with bows and plates
o Follow lines of stress
§ Fluid connective tissues – blood and lymph
· Blood – plasma; transports nutrients and oxygen to tissue
o Red blood cell – transports oxygen to nucleus; hemoglobin turns blood red
o Platelets – help seal injured blood vessels; fragments of larger cells
o White blood cell – fight infection, have nucleus
· Lymph – clear, watery
o Derived from tissue fluid containing white blood cells
o Lymph transported to cardiovascular vessels
o Muscular
§ Three types: skeletal (can be felt on outside of body), smooth (internal, moves digestive tract), cardiac (heart, rhythmic beating)
§ Allows body movement
§ Made of muscle fibers/cells, actin, and myosin, of which the last two are protein fibers that allow movement
§ Skeletal muscle (voluntary muscle)
· Striated cells (striped appearance) with multiple nuclei
· Occurs in muscles attached to the skeleton
· Functions in voluntary body movement
· Cylindrical, long muscle fibers
§ Smooth muscle (visceral)
· Spindle-shaped cells, each with a single nucleus
· Cells have no striations
· Function in movements of substances in lumens of the body
· Involuntary
· Found in blood vessel walls and digestive tract walls
· Nuclei form irregular tissue pattern
§ Cardiac muscle
· Has branching striated cells, each with a single nucleus
· Occurs in only the wall of the heart
· Functions in blood pumping
· Involuntary
· All cardiac muscles bound end-to-end by intercalated disks
o Nervous
§ Two major nervous tissue cell types: neurons (carry messages), neuroglia (support neurons in various ways)
§ Allows inter-cell communication via sensory output, integration of data, and motor output; travels almost like electron messages
§ Neurons – nerve cells
· Dendrite – extension that receives signals from sensory receptors on other neurons
· Cell body – most of cell’s cytoplasm and nucleus
· Axon (a fiber) – extension that connects nerve impulses – long ones covered in myelin (white fatty substance)
§ Neuroglia
· Outnumber neurons 9-1, make up more than half of brain volume
· Primary function – support and nourish neurons
· Types of brain neuroglia
o Microglia – engulf bacteria and cellular debris
o Astrocytes – provide nutrients to neurons and produce hormone glia, a derived growth factor
o Oligodendrocytes – form myelin sheaths around brain fibers and spinal cord fibers
o Schwann cell – outside of brain, encircle long nerve fibers and form myelin sheath
o Epithelial
§ a sheet of cells that lines the body in a tight, continuous network
§ Found in glands, lining body cavities, covers body surfaces
§ Cells anchored by bottom (basement) membrane on one side and free on the other (forms sheet)
§ Different types of epithelial tissue named according to the shape of the cells, as well as the cell layers, e.g. transitional epithelium
§ Protective function
§ Five types of epithelial tissue: simple, pseudostratified columnar, transitional, stratified, glandular
· Simple epithelia – single layer of cells; classified according to cell type
· Simple squamous
o Lining of lungs and blood vessels
o Protects
o Shaped and arranged to permit exchange of substances
· Simple cuboidal
o Lining of kidneys, tubules, various glands (e.g. salivary gland, thyroid gland), pancreas
o Absorbs molecules
· Simple columnar
o Lining of small intestine, oviducts
o Absorbs nutrients
o Goblet cell section (mucus)
· Pseudostratified (ciliated) columnar
o Lining of trachea
o Sweeps impurities toward throat
o Has cilia and goblet cell (secretes mucus)
· Transitional
o Changes in response to tension
o Lines bladder, ureters, and urethra
o Found in organs that need to stretch
o Similar to columnar epithelia
· Stratified squamous
o Layers of cells piled on top of each other
o Lining of nose, mouth, esophagus, anal canal, vagina
o Protects
o Outer layer of skin it stratified squamous with reinforced cells
· Stratified columnar is found in body
· Stratified cuboidal is found in body
· Glandular
o Defined by secretion
o Can contain one or many cells
o Glands with excretion ducts called exocrine glands
o Ducts simple or compound
o Ductless gland is called an endocrine gland (e.g. thyroid gland)
o Cancers are categorized by the four tissue types
· Cell junctions
o Epithelial cells, and sometimes muscle and nerve cells, are connected by cell junctions
o Help tissue perform its particular function
o Three types of junctions: tight, adhesion, gap
§ Picture of a tight junction
(found at http://www.virtuallaboratory.net/OmniaCellula/Contents/Topic6-3_Adhesion.htm)
§ Picture of a gap junction
(found at http://www.answers.com/topic/gap-junction)
§ Picture of an adhesion junction
(found at http://en.wikipedia.org/wiki/Desmosome)
· Skin and accessory organs – an integumentary system
o Skin most conspicuous system; 15% body weight
o Numerous functions – protecting, regulating body temperature, helping maintain homeostasis, produces vitamin D
o Regions of skin (top to bottom):
§ Epidermis – sweat pore, stem cells
· Made up of stratified squamous epithelium
· New epidermis cells derived from stem cells
o New skin cells harden as they rise to the surface because of keratin
· Langerhans cells deep in the epidermis; type of white blood cell
· Melanocytes – deep in epidermis; produce melanin (main skin color pigment)
· Small amount of UV radiation causes skin to produce vitamin D, which is then absorbed and used internally
· Too much UV radiation causes skin cancer, basal cell carcinoma, and melanoma
§ Dermis – sensory receptacles, capillaries, oil gland, arrector pili muscles, free nerve endings, hair follicle, hair root, sweat gland, artery, vein, nerve
· Contains collagen, elastic fibers and blood vessels that nourish skin (dilate when warm, contract when cold)
· Sensory receptors for touch, pressure, pain, hot, cold
§ Subcutaneous layer – adipose tissue
· Technically not part of skin
· Made of loose connective tissue and adipose tissue (stores fat, helps thermally insulate)
o Accessory skin organs – hair, skin, nails
§ Nails
· Protective covering of digits
· Grow from epithelial cells in nail root
· Cuticle hides nail root
· Luluna (white nail near root) made of thick layer of cells
· Nail cells become keratinized as they grow out over nail bed
· Diagram of nail anatomy
(found at http://anatomy.iupui.edu/courses/histo_D502/D502f04/lecture.f04/integument.f04/integumentf04.html)
§ Hair (follicle)
· Begins at a bulb in the dermis, continues out past epidermis
· Dark if melanin by melomocytes present in bulb; blonde or red if melanin contains iron and sulphur; gray if melanin cannot be produced
· Contraction of arrector pili muscle attached to hair follicles causes hair to “stand on end” (goose bumps)
· Epidermal cells form hair root
· Hair cells become keratinized and die as they are pushed farther from root
· Each follicle has one or more oil glands that secrete sebum (an oily substance that lubricates skin and hair in the follicle
§ Sweat glands
· Numerous and on all skin
· Is a tubule that begins in the dermis and opens into hair follicle or skin surface
· Help modify body temperature, become active when body gets warm; sweat absorbs heat as it evaporates
· Stop working when body temperature lowers
· Organ systems
o Integumentary system
§ Consists of: skin, nails, hairs, muscles (that move hairs), oil and sweat glands, blood vessels, nerves leading to sensory receptors
§ Many homeostatic functions
§ Protects body, receives sensory input, helps control temperature, synthesizes vitamin D
o Cardiovascular system
§ Transports blood, nutrients, gases, and wastes
§ Defends against disease
§ Helps control temperature, fluid, pH balance
§ Heart pumps blood into blood vessels
§ Blood distributes heat production from muscles
· Red blood cells transports oxygen and nutrients to cells and removes carbon dioxide and other waste
· White blood cells fight infection
· Platelets involved in blood clotting (wounds)
o Lymphatic and Immune system
§ Lymph vessels – nodes, spleen, other lymph organs
§ Immune system is made up of all the cells in the body that protect us from disease; e.g. lymphocytes
§ Helps control fluid balance
§ Absorbs fats
§ Defends against infections and diseases
§ Purifies lymph, transports it to cardiovascular veins
o Digestive system
§ Mouth, esophagus, stomach, small intestine, large intestine (colon), teeth, tongue, salivary glands, liver, gallbladder, pancreas
§ Ingests and digests food; absorbs nutrients; eliminates waste
o Respiratory system
§ Lungs, connected tubes for air
§ Receives oxygen, removes carbon dioxide; maintains breathing; exchanges gasses in lungs and tissues; helps control pH balance
o Urinary system
§ Kidneys, urinary bladder, tubes to carry urine
§ Excretes metabolic wastes (kidneys); helps control fluid and pH balance
o Skeletal system
§ Supports body; protects body parts (e.g. brain), helps move body; stores minerals (e.g. calcium); produces blood cells
o Muscular system
§ Maintains posture; moves body and internal organs; produces heat
o Nervous system
§ Brain, spinal cord, associated nerves
§ Allows us to respond to external/internal stimuli
§ Receives sensory input, integrates and stores input; initiates motor output
§ Helps coordinate organ systems
o Endocrine system
§ Hormonal glands – secrete hormones into blood stream
§ Produces hormones; helps coordinate organ systems; responds to stress; helps regulate fluid and pH balance; helps regulate metabolism
o Reproductive system
§ Male – testes, everything related to semen and penis (sperm)
§ Female – ovaries, oviducts, uterus, vagina, external genitals (eggs)
§ Produces and transports gametes; produces sex hormones
§ Nurtures and gives birth to offspring (in females)
o Here are two pictures of the body systems with highlighted organs
· (found at http://trc.ucdavis.edu/biosci10v/bis10v/week10/07organsystems.html)
· (found at http://trc.ucdavis.edu/biosci10v/bis10v/week10/systems2.gif)
· Body cavities
o Ventral
§ Thoracic cavity – heart, lungs, esophagus
§ Abdominal cavity – stomach, liver, spleen, pancreas, gallbladder, intestines
· Diaphragm is between thoracic and abdominal cavities
§ Pelvic cavity – reproductive (and other) organs
o Dorsal
§ Cranial cavity – brain
§ Vertebral cavity – spinal cord
· Body membranes – line cavities and internal organ spaces and tubes to outside
o Mucous – line digestive, respiratory, urinary, and reproductive systems
§ Means the membrane secretes mucous
o Serous – line lungs, heart, abdominal cavity and its internal organs
§ Pleura – lines thoracic cavity and over lungs
§ Pericardium – forms pericardial sac and covers heart
§ Peritoneum – lines abdominal cavity and covers its organs
· Peritonitis – life-threatening infection of peritoneum
· Mesentery – double peritoneum that supports abdominal cavity and attaches them to the abdomen wall
§ Secretes watery fluid, keeps membranes lubricated
§ Supports internal organs
§ Compartmentalizes thoracic and abdominal cavities
o Synovial – loose connective tissues that line the cavities of freely movable joints
§ Secrete synovial fluid into joint cavity, lubricates ends of bones
o Meninges – found in dorsal cavity; composed only of connective tissues and serves as a protective covering for the brain and spinal cord
· Homeostasis – body’s ability to maintain relative constancy of its internal environment by adjusting its physiological processes; limits internal change so conditions usually stay within a narrow normality range
o Negative feedback – the primary homeostasis mechanism that keeps a variable close to a particular value
§ Has two components – sensor, control center
· Sensor detects change
· Control center brings about effect to normalize condition
o Sensor and control center both located in part of the brain called the hypothalamus
· When system returns to normal, sensor is no longer activated
§ Here is an everyday example of how the negative feedback system works
(found at http://www.colorado.edu/eeb/web_resources/cartoons/homeo.html)
· Positive feedback – a mechanism that brings about an ever greater change in the same direction, e.g. childbirth or fever (both loop to definite cut-off point)
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