Anatomy lect 15+, A&P Midterm 1, Anatomy Midterm 2

When we talk about the sarcomere shortening, what does this mean in terms of the thick & thin filaments? What happens to the zone of overlap and to the distance between z lines/discs during muscle contraction? What happens to the width of the H zone, I band and A band?

Sliding filament theory Zone of overlap increases during shortening Distance between Z discs decreases Width of H and I zones shorten A band stays the same...

8.What is muscle tissue specialized to do? + types

Specialized for contraction - Produces all body movement Three types: 1) *Skeletal muscle* - LArge body muscles responsible for movement 2) *Cardiac muscle* - Found only in heart 3) *Smooth muscle* - Found in walls of hollow, contracting organs

Study Q: What determines function? Give an example.

****Key concept**** All physiological functions are performed by specific anatomical structures *Structure determines function*

Current vs. Potential

*Current* = flow of electrical charge - Ions can make current *while crossing the membrane* - Make current BOTH while moving through pumps and channels *Potential* = difference in charge across membrane (relative from inside to out) - Created by differential concentrations of ions across membrane

Depolarization, repolarization, and hyperpolarization definitions

*Depolarization* - A shift in transmembrane potential toward or above 0 mV (positive shift from rest) - Caused by Na+, Ca++ channels opening. Both rush in *REpolarization* - When stimulus is removed, transmembrane potential returns to normal *Hyperpolarization* - A shift in transmembrane potential below resting - Caused by Cl- and K+ channels opening. Cl- rushes in, K+ rushes out Return to resting potential - Last phase of action potential, after hyperpolarization

Study Q: What is meant by gross anatomy and microscopic anatomy? What is meant by cytology and histology?

*Gross (macroscopic) anatomy* - Deals with large, visible structures ----------------- *Microscopic anatomy* - Deals with cells and molecules > *Cytology* - Cells and their structures (cyt=cell) > *Histology* - tissues and their structures

Study Q: What is meant by homeostasis? Why is the concept of homeostasis so important in the study of living organisms? What are homeostatic ranges?

*Homeostasis* - Responding to a stimuli to regulate a variable - Every cell maintains homeostasis: organs, organ systems, and organisms may maintain homeostasis - If your body doesn't maintain stability, you die Homeostatic ranges are samples mainly from white males that represent a narrow "norm" - So just because something is out of a range, does not mean it's homeostatically unbalanced

3.What does the skin protect against?

- Abrasion - Chemicals - Foreign pathogens

Muscle relaxation - Return to rest

- Ach is removed by acetylcholinesterase, or diffuses away - Active transport of Ca++ into SR (pump always active) > No actin or myosin interaction - Active sites covered again by tropomyosin - Sarcomeres remain contracted until passive recoil of elastic components ---------- Return to rest - Gravity, antagonists, elastic elements Prevent overstretching - Titin, bone arrangement (pull), connective tissues

Study Q: 2. What are the functions of: Ribosomes e. Why are some proteins made in the rough ER and some made by free ribosomes in the cell? *She care a lot about difference between free and bound ribosomes

- Make proteins e. Different destinations. Rough ER is exported. Free ribosomes are for proteins in the cell.

Cell

- PErforms all life functions - Basic structural + functional unit of life > Respond to the environment > Maintain internal fluid homeostasis > Modify structure+function over time Lots of variation!

Study Q: 2. What are the functions of: Microvilli

- These are outfoldings of the plasma membrane - Increase surface area for absorption/secretion - So small that you can't see them in light microscope ("brush border")

If Ca++ and ATP continue to be present, is the crossbridge cycle a single event or a repeated event? Are all of the myosin heads in a sarcomere binding to actin, pivoting and then releasing from actin all at the same time (in unison)?

------------- If Ca++ and ATP are still present, the crossbridge cycle is a repeated event ------------- The myosin heads don't act in unison (otherwise the muscle wouldn't shorten) - Rope anchor analogy "asynchronously cycling" - Some myosin need to be attached at once, or else thin filament would fall back to resting potential

b.There are 3 types of extracellular protein fiber in connective tissue: collagen, elastic fiber and reticular fibers. Where did these fibers come from (what cells produced them)? What do you think are properties of elastic fibers? How would changing a connective tissue's fiber type change the function of the tissue? Suggest an example.

--------------------- b) Fibers in CT are made by fibroblasts - Elastic fibers can stretch probably - Changing the CT's fiber type may change its properties like: Elastic replaced by collagen would be less stretchy and also stronger. So an organ may not be able to change its shape adequately to function. Locations a) *Collagen fibers* (strong, most common in *tendons* + *ligaments*) b) *Reticular fibers* (stroma of organs) c) *Elastic fibers* (elastic ligaments)

Endocytosis and exocytosis

-Always active Endocytosis - Phagocytosis (swallowing large) - Pinocytosis (sipping small) Exocytosis - Blebbing stuff out

You should look at muscular system animations and activities as well as the nervous system (the ion channels and membrane potential sections will be most useful).

...

10.How will you tell these tissues apart under the microscope?

... Nervous - presence of star-shaped glial cells. Lots of space CT - few cells, lots of ECM Muscles - dense cells + striations (usually). Usually parallel - fibers + protien inside cell Epithelial - dense cells, fairly homogenous. Have an apical surface (not connected to tissues), so can find lumen (light)

What is the power stroke of muscle contraction? During the power stroke, what happens to the myosin head? What happens to the thin filament?

... Power stroke is when myosin head pivots towards the M-line, pulling thin filament towards M line too

Regarding ATP and the crossbridge cycle: How many ATP molecules are required for a single crossbridge formation? When is ATP required in the contraction (crossbridge) cycle? When during the contraction (crossbridge) cycle is ATP split into ADP and Pi? Energy is released during this chemical reaction. Where does the energy released during ATP splitting go?

1 ATP per crossbridge formation ATP is required for breaking the crossbridge It is split when myosin head is being reset - Energy released goes into the myosin head

Transmembrane proteins of the cell membrane

1) Carrier proteins - Aids in facilitated diffusion of a specific chemical - Substrate binding causes conformation change, transporting the protein 2) Channel proteins - Mostly ions, based on size and charge - Opens a hole in the membrane for some substances - Osmosis is a special case of this (uses aquaporin OR lipid bilayer) > Simple + facilitated diffusion

PArts of the integument

1) Cutaneous membrane (Skin) a) Epidermis b) Dermis 2) Accessory structures a) Hair b) Glands (sweat + sebaceous) c) Nails ^ Epidermal structures that are embedded in the dermis 3) Hypodermis Ectoderm > epidermis MEsoderm > dermis

What causes resting membrane potential?

1) Different concentrations of ions outside and inside cell (concentration gradient) 2) Ions moving across cell membrane (membrane permeability) - Actively - Sodium/potassium pump - Passively - channels In a neuron, it's equal to around -70 mV

1.During early development, there exist 3 primary germ layers which give rise to particular parts of the adult body. 4.What are the three primary germ layers? Are these the first cells of the zygote? a.Which gives rise to the epithelium of the skin and to all neural tissue? b.Which gives rise to most connective tissue and muscle? c.Which gives rise to gut (and lung) epithelial lining?

1) Endoderm - Epithelial lining + glands of digestive/respiratory tracts 2) Mesoderm - Vertebrae + ribs, dermis of dorsal body region, trunk + limb musculature, kidneys, gonads, dermis of ventral body region - Connective tissue of limbs (bones, joints, ligaments) - walls of digestive + respiratory tracts (except epithelial lining) - HEart, blood vessels 3) Ectoderm - Brain + spinal cords - Nerve associated stuff - Epidermis, hair, nails, glands of skin These are not the first cells of the zygote. Zygote > blastula (hollow ball of cells) > gastrula (which gives rise to germ layers)

How does your body vary force production in a fiber?

1) Frequency of APs - More = more force 2) Number of myofibrils - More myofibrils = more force 3) Length of muscle - Longer/shorter = Less - Medium = max force

How does your body vary force production in a whole muscle?

1) Frequency of APs - More = more force 2) Number of myofibrils - More myofibrils = more force 3) Length of muscle - Longer/shorter = Less - Medium = max force 4) Number of motor units recruited

Types of channels in cell membranes

1) Leak channels - Always open - Ion specific 2) Gated channels - Open and close in response to a specific signal a) Voltage gated - Action potentials b) Chemically gated (ligand) - Graded potentials c) MEchanically gated - Opened by physical force on cell

Types of connective tissue

1) Loose CT: Areolar - General packaging material of body - Chicken soup w/ a few noodles - Fibroblasts = chicken - Noodles = collagen 2) Loose CT: Adipose - Contains many adipocytes - Adipocytes in adults do not divide > Expand to store fat. Shrink as fats are released 3) Dense regular CT - Attachment/stabilization - Tightly packed, parallel collagen fibers - *Tendons* = attach muscles to bones - *Ligaments* = bone to bone and stabilize 4) Dense irregular CT - STrength in many directions - Interwoven networks of collagen fibers > Layered in skin > Around cartilage and bones > Form capusles around some organs (liver, kidneys, etc) Supportive CT 5) Cartilage - Gel-type ground substance - For shock absorbance and protection 6) Bone - Calcified (made rigid by calcium salts, minerals) - For weight support

4.What are the four primary tissue types and their basic functions (or locations)? Which tissues are highly cellular? Which tissues create movement? Which tissues are specialized for communication?

1) Nervous - Send signals 2) Muscle - Generate movement - Highly cellular 3) Epithelial (lining inside and outside of body) - Protection, permeability - Highly cellular 4) Connective - Found throughout the body (connecting muscles, blood, bones, fat) - Support, transport

1.How is signaling using hormones similar to neuronal communication using neurotransmitter? How is it different? 2.What are hormones? 3.What determines if a hormone can affect a target cell? 1. What are the different ways cells communicate with each other?

1) Nervous system (Neurotransmitters) - Electrical + chemical signals over short distances - Fast - Short lived 2) Endocrine system (Hormones) - Chemical signals that travel through blood over long distances - Long-lived effects - Slower to start Similar - Both cause a change in the target cell - Both require receptors to have effects - Both use chemicals (at some point) -------------- A chemical released from endocrine glands/organs to interstitial fluids - Travel through blood Cause a change in a receptor cell

Classification of epithelial tissue + functions of specific classes

1) Number of layers - Simple vs. stratified 2) Shape of cell at apical surface - Squamous (pancake) - cuboidal - Columnar --------------- 1) Stratified squamous - Protects against attacks - *Keratin* proteins add strength + water resistance - Oil between cells 2) Simple squamous - Thin barrier, allows diffusion 3) Glandular epithelia - Cuboidal ro columnar - Release hormones into interstitial flood, blood - no ducts Overall, structure determines function - resistance = stratified - Simple = allow passage

Study Q: What three components are required for true homeostatic regulation of specific human physiological parameters?

1) Receptor - Like a thermometer, it measures level of the variable 2) Control center - Thermostat/brain - Receives/interprets info ends commands to effector to regulate change 3) Effector - Carries out command. Activates bodily responses to regulate variable to the set range

Study Q: a. What are the 2 basic components of the cell membrane? Which of these allows small non-charged substances & fats to enter/leave the cell? Which of these allows charged or large particles to enter/leave the cell?

2 basic components: 1) Phospholipids (fats) - Hydrophillic heads - toward watery environment, both sides - Hydrophobic fatty acid tails - inside membrane - Form a lipid bilayer 2) Proteins - CAn act as enzymes, anchoring, recognition, or transport 3) carbohydrates ------------------ Phosopholipid tails allow small, noncharged substances (fat soluble molecules) to pass - Ex. Alcohols, O2, CO2, water Protein channels may allow large/charged particles to enter/leave -------------------- Pumps help to *create a gradient* - pump against gradient (opposite of normal flow, so takes energy)

What is a crossbridge? When does it form?

A crossbridge is formed when Myosin (thick filament) binds to the active site of Actin (thin filament) It forms when muscles receive a signal to act and Ca++ binds to troponin (which exposes actin binding sites by moving tropomyosin)

CCQ: In the condition myasthenia gravis, the chemically gated channels that bind Ach are gradually destroyed by the person's immune system. Would this person be improved by a stimulating device?

A little, because more ach would be released, so the remaining channels could be activated more.

Describe the muscle contraction event from the action potential generation in the sarcolemma through the crossbridge cycle (to the reactivation/recocking of myosin). What are the major players in this process?

A) Action potential generated in sarcolemma travels down T-tubules B) Triggers opening of Ca++ release channels on SR C) Ca++ binds to troponin, which moves tropomyosin and exposes myosin binding sites on actin ------ 1) Rest - Myosin heads are cocked back. Bound to ADP + Pi - Myosin in high energy state v Ca++ binds to troponin 2) With exposure of binding sites, cross bridge is formed - Pi is lost in crossbridge formation, ADP still bound to myosin - Myosin still in high E state 3) Pull back thin filament towards M line - ADP is lost as myosin head pivots towards M line - Myosin in low E state > Stored energy becomes kinetic 4) Myosin detaches w/ use of 1 ATP - Myosin in low E state (energy in ATP) - *cycle starts here* 4.5) Myosin head reset - ATP is split into ADP and Pi, and myosin cocks back. Ready to do cycle again *One cycle takes 1 ATP*

CCQ: 5.In the stomach and small intestine, the epithelium is resistant to acid, but deeper structures are not. What would happen if a bacterium disrupted the cellular junctions between stomach epithelial cells?

Acid could reach deeper cells and cause tissue damage (probably cell death and issues in organs/organism)

What factors are necessary for continuous muscle contraction? When nervous system stimulation stops, what happens in the muscle cell? When calcium stores are depleted, what happens to the muscle contraction? When ATP stores are depleted, what happens to the muscle contraction?

Action potentials from motor neuron - Ca++ and ATP When nervous system stimulation stops, Ca++ is gradually pumped out of the sarcoplasm into the SR, and myosin binding to actin becomes less frequent - Muscle relaxes (lenghens) due to elastic components When Ca++ stores are depleted, similar effect to the above When ATP stores are depleted, muscles remain contracted because crossbridge can't be broken

When a muscle cell receives a signal from a motor neuron, are all the sarcomeres activated or only some?

All sarcomeres of a myofibril are activated and all myofibrils of a myofiber are activated when myofiber (muscle cell) is activated (see quiz)... All or none principle of muscle activation This is also true for motor unit

What is anatomy and physiology? ------ Study Q: Generally speaking, what does the study of anatomy and physiology tell you about structure and function relationships in the human body?

Anatomy describes the *structures* of the body - What they are made of - Where they are located - Associated structures (the relationships) ----------------- The study of *functions* of anatomical structures - Individual and cooperative functions

Study Q: Why do cells differ in their organelle composition?

Because they need different anatomy to carry out their different functions

CCQ: b. Lactose is a milk sugar digested by lactase, a membrane bound digestive enzyme located on cells of the small intestine. What do you think it means to be lactose intolerant? Where could the issue originate (what are possible sources of dysfunction)?

Being lactose intolerant means that there is some issue with lactase (a lack, an inactivation, etc) that makes people unable to digest lactose. May be genetic

7.What can you say about connective tissue (CT) in general? 6. How does connective tissue contribute to the framework of the body - where are connective tissues (CT) found? What are some of their functions?

CT contributes to the framework of the body by being found throughout it (in bone, blood, fat, tendon, ligaments, etc). Functions - Fills internal spaces - Supports other tissues - Transport materials - STore energy - Protect/insulate - Isolate

5.What is a tissue (how is it different from and related to a cell or an organ)?

Cell < tissue < organ A tissue is many cells working together to perform a common function. Different tissues make up organs.

Study Q: Using proteins as an example, how do cells vary in organelle composition to match cellular function?

Cells exhibit different proteins (ex. Neurons may have more sodium potassium pumps in order to make action potentils). Cells that make lots of proteins for export may have more Rough ER, golgi apparatuses, and vesicles, while ones that make proteins for the cell may have more free ribosomes.

STudy Q: 2. What are the functions of: Centrioles Cytoskeleton

Centrioles - Ensure that equal amounts of genetic material go to each daughter cell in cell division. - Essential for movemnt of chromosomes during cell division Cytoskeleton (generally, not the specific filaments/tubules) - Structure, transport of molecules (serves as tracks) - Strength, cell contraction

9.What is neural tissue specialized to do? + extra info

Convey signals (through electrical signals and chemical synapses) - Rapidly sense internal or external environment - Processes information and controls responses - Neural tissue is concentrated in central nervous system (Brain + spinal cord) 2 types of neural cells - NEuron - nerve cells - Neuroglia (support cells)

Study Q: 2. What are the functions of: b. Rough ER c. Smooth ER

Endo (within) - plasm (cytoplasm) - reticulum (network) Rough ER - Has ribosomes attached - Makes proteins Smooth ER - No attached ribosomes - Carbohydrates and lipids synthesis - Cisternae here store synthesized molecules Functions: - Synthesis - Also transport functions in ER - Detoxification of drugs/toxins

CCQ: 7. As a histologist, you find a tissue that is composed of many cells tightly packed together. The cells are unattached at one surface, but firmly anchored to connective tissue at the bottom. What type of tissue is this? Where might you find this particular tissue? a. You are still a histologist. Now you have found a tissue that is composed of many extracellular fibers tightly packed together. There are some cells, but they are not terribly abundant. What type of tissue might this be? Where might it have come from?

Epithelial (basal + apical surface). May be found lining organs or skin a) Connective tissue - Tendons, ligaments, fats, etc

CCQ: 2.The liver is responsible for production of most, if not all, transport proteins for fat soluble hormones. What do you think would be a consequence of liver failure to make these transport proteins?

Fat soluble hormones wouldn't be able to reach their destinations, so all those functions would fail. Possible death

3.What are the functions of the integument and hypodermis? a.Which vitamin is synthesized in the skin, what is its active form and what does the active form do (see study questions from bone as you may have already answered this)?

Functions: 1) Protection 2) Excretion + absorption (absorb sunlight, synth. vitamin D) 3) Thermoregulation 4) Synthesis 5) Sensation 6) Storage (fat) a) Vitamin D3 is synthesized in skin. It's active form is Calcitriol - Helps in calcium and phosphorus absorption

Study Q: 2. What are the functions of: Golgi apparatus [Lysosomes]

Golgi function: - Repackaging (especially of export proteins) - Transport vesicles > Secretory vesicles > Membrane renewal (and removal) vesicles Lysosomes - hold digestive enzymes - Removal of damaged organelles or pathogens

Study Q: How does a cell come to have different cellular compositions? (By what mechanism does this occur)?

Have different functions, needing different organelles. It has different cellular composition via different gene expression.

CCQ: 3.What would happen if the kidney and liver could not remove hormones from the body? What would be the effect on the glands that produce those hormones and what would be the effects on the target cells?

Hormones would continue to exert their effects at the wrong times, causing dysregulation and general dysfunction The glands may make less hormone (if affected by density) or be inactivated by the body (if possible). The target cells would be over active for a while, but may eventually down regulate receptors

CCQ: 4.What would happen if the kidney and liver removed too many hormones from the body? What would be the effect on the glands that produce those hormones and what would be the effects on the target cells?

Hormones would have lesser effects or not be able to act at all. The glands might try to make more to compensate, and the cells might upregulate receptors

5.How would diseases affecting mitotic rate of cells impact the epidermis?

IF they decrease mitotic rate of cells, the epidermis may become frail, or even permeable in places If they increase the mitotic rate of cells, the epidermis may become too thick for the amount of wear and tear it is subjected to

CCQ: 6.What would happen if collagen fibers could not be formed properly? What tissues would be most affected and what symptoms might this particular problem cause?

If collagen fibers couldn't be formed properly, you'd have issues in bones and connective tissues. Bones may be extremely brittle, and connective tissues would lack a key structural component and may be incomplete/fragile.

Why are mitochondria necessary in skeletal muscle cells? What processes in a skeletal muscle require ATP? (Remember to consider pumps...)

Mitochondria are necessary because ATP is needed to break the cross-bridge and continue the cycle that shortens the muscle - And mitochondria makes ATP - Active pumping of Ca++ into SR - Breaking crossbridge

1.Why does the epidermis have so many epithelial cells? Why are there more cells in the epidermis of certain parts of your body compared to others?

It has many cells because it experiences lots of abrasion, so the layer needs to be thick to protect the body There are more on some areas because those areas experience more abrasion (ex. hands, feet). Growth influenced by stress.

Study Q: What happens if homeostasis is not maintained at the cellular level?

It will cause structural change at every level above it (potentially) - Structure determines function

CCQ: 1. How would the absence of synapsin (the protein holding reserve synaptic vesicles) affect neurotransmitter release (assume NT production and reuptake still occur)?

It would make it so that more neurotransmitter is released (per influx of calcium), but that the cell may have trouble releasing neurotransmitter inbetween (since reuptake and production rate has not changed) Synapsin normally holds these things in the recycling pool, and calcium influx triggers the release of these things

4.Is the skin waterproof? How do you know?

It's not water proof, because water can move through it (pruning in a pool). But keratin adds some water resistance to stratified squamous epithelium.

6.What is the most important intracellular protein to epidermal cells, hair and nails?

Keratin

Study Q: Starting with the simplest, what are the levels of organization in living organisms that we discussed in lecture (see lecture notes)? Be able to arrange these levels from simplest to most complex. Give specific example of levels of organization and assemble them into their proper order.

Levels: Atom < Molecule < organelle < cell < tissue < organ < organ system < organism

3. What is the difference between lipid soluble and water soluble hormones in terms of transport through the blood and receptor location at target cells? Why do water soluble hormones require a second messenger? Why can the effects of water soluble hormones be more dramatic than fat soluble hormones, despite the fact that fewer molecules of water soluble hormone may be present?

Lipid soluble - Requires a blood transport protein (bc lots of water in blood) - Receptor is inside the cell - Genomic effects (direct gene activation) - Slow, long-lasting Water soluble - Can dissolve into blood - Receptor outside on cell membrane - FAst bc 2nd messenger is waiting + ready to go. Don't need to produce things - Amplifying - Cleared quickly ---------- Water soluble hormones require a second messenger system because they can't pass through the cell membrane, and must do effects indirectly. ----------- Water soluble hormone effects can be more dramatic because they trigger signal cascades (1 molecule => big effect). Often coupled to G-protein

Sodium-potassium pump

Na+ - Out (both have 3 letters, which is how many are pumped) - Na+ high out of cell K+ - In (both have 2 letters, which is how many are pumped) - K+ high in cell "Pump" = active transport, takes ATP -------------------- - Present on every animal cell (in high concentrations) - Always pumping (even when cell is *resting* (not sending/receiving signals)) - Establishes concentration gradients ---------------------

Will myosin detach from actin if ATP is not present? Why is the ability to produce ATP so important in skeletal muscles?

No (ATP is required for breaking of crossbridge)

Study Q: 4. What is the nucleus? What is its function? What is DNA? (Use your notes and chapter 3 to help here.)

Nucleus - The cell's control center - Contains the code (DNA) for protein structures of cell & therefore functions of cell - For somatic cells, they generally have the same DNA

What is the relationship between number of crossbridges (or crossbridge cycles) formed and the amount of tension a muscle cell can generate at a given time?

Number of crossbridges formed is positively correlated with amount of tension generated

Study Q: What is the relationship between cell composition (number of certain organelles) and cell function? Do all cells have the same organelles and number of those organelles?

Number of organelles are based on the cell's needs (function). So cells have differing numbers, and may lack certain organelles

What is the relationship between number of crossbridges (or crossbridge cycles) formed and the amount of tension a whole muscle can generate at a given time?

Positive relationship (no plateau)... Direct relationship between muscle force and number of crossbridges formed

Graded potentials

Proportional to the size of stimulus - More ions enter Affects channels near them, as the released ions spread - This "pond ripple" gets weaker further from the source - They're unpredictable because of how much they can vary Ex. When positive ions enter, bumps positive charge down membrane to a certain degree

Study Q: Why can a cell interior vary from its exterior in terms of ionic composition (what creates this difference)?

Pumps, channels, and also differing permeability for certain ions.

In the muscle contraction (crossbridge) cycle, what is the "energetic status" of myosin at rest? When myosin is in the high energy state, where did the energy come from? When myosin is in the high energy state, what is the position of the myosin head? What molecules are bound to the myosin head in a resting fiber?

Rest - High energy In high E state, energy came from ATP, and myosin head is cocked back (ready to act) - Also when cross bridge is formed, but before it pivots Molecules bound = ADP + Pi

a.How would you characterize CT anatomically? (What are the basic components of CT? Think cells and matrix...)

Structure 1) Cells - Few 2) Matrix (extracellular parts) - Unique to each CT - MAjority of CT A) Solid = *protein fibers* B) Fluid = *ground substance* > Stuff in ECM that ISN'T protein fiber > Fills spaces between cells > Varied composition (water, mineral, some dissolved compounds) Specialized cells 1) Fibroblasts/fibrocytes (make fibers in CT) 2) Blood cells 3) Adipocytes (fat) 4) Osteocytes (bone) 5) Chondrocytes (cartilage)

Study Q: What is the cell membrane? What are its functions?

Structure: - Bilayer consisting of lipids, carbohydrates, and proteins - Prtoeins act as enzymes, anchoring, and recognition of transport ---------------- Cell membrane functions: 1) Isolation/protection > Intracellular fluid (cytosol) > Extracellular fluid (interstitial fluid if in tissues) 2) Regulation 3) Sensitivity 4) Support

CCQ: A human egg (ovum) must support all cellular division once fertilization is complete. What organelles would you expect it to have? Bonus: Which of these organelles originated from the sperm?

The zygote should have all organelles (nucleus, golgi apparatus, mitochondria, vesicles, lysosomes, peroxisomes, etc). The sperm doesn't have many, but it at least contributes its genetic info (nucleus) and mitochondria for energy (maybe not mitochondria though). Also has a modified golgi for secretion *Should be able to extrapolate what cells will have based on key info

CCQ: Suppose a compound (drug) caused the sarcoplasmic reticulum calcium channels to remain open. What would happen in your muscle cells? What would happen to your body temperature? How would you reverse this?

There would be strong contraction for a time, but eventually lead to cramping due to ATP depletion... Body temp increases due to energy being lost in creation of ATP Provide ATP... or make a drug that closes channels

Study Q: 2. What are the functions of: Cilia Flagella

These are made of similar substances (not important to know that) Cilia - Move fluids across cell surface - Visible under light microscope Flagella - Cell mobility - Only on sperm in humans

2.Where are keratinocytes initially formed?

They are initially formed in the stratum basale. Migrate to stratum corneum

Study Q: At rest, are ions crossing the cell membrane? Are pumps active?

They are. They're always moving down their concentration gradients, when available. The sodium-potassium pump is also working to maintain the concentration gradient, so yes.

Must muscles (muscle tendon units) change length to generate tension? When do you use isometric and isotonic contractions? B) What controls whether you activate a muscle isometrically or isotonically? ------------ A) Do myosin and actin form crossbridges in isometric muscle activations? What about in isotonic muscle activations?

They do not have to change length (because they have elastic fibers) --------------- Isometric - Load force = muscle force Isotonic - Two kinds: A) Concentric = muscle force > load force B) Eccentric = muscle force < load force > Myosin trying to engage and pull, but load is tearing myosin heads off of thin filament ------------- The crossbridges form in both

CCQ: Suppose blood flow to a muscle is restricted by a blood clot. Why might this muscle cramp (a sustained contraction)?

This may lead to a muscle cramp because muscles aren't getting the nutrients needed to make adequate ATP to release the crossbridge...

Study Q: b. How does water cross the cell membrane? c. How does oxygen cross the cell membrane? d. How does sodium cross the cell membrane?

Water - osmosis (simple diffusion) Oxygen - simple diffusion Sodium - Facilitated diffusion (charged ion)

What would be the effect of sustained sarcoplasmic calcium but the absence of ATP? (This state occurs during rigor mortis.) CCQ: How would loss of ATP affect a muscle cell?

You go through one cycle, but then remain contracted bc crossbridge can't be broken - Can't get any shorter

6.What can you say about epithelial tissue? 5.For epithelia: a.What are the five characteristics that all epithelia share?

a) All share 1) It has high cell density (more cell than ECM). - *cell junctions* - Multiple layers 2) Polarity - Has an *apical surface* (free) and *basal surface,* 3) Avascularity - No blood supply - Need to be close to blood supply to get nutrients (top layer dead) 4) Attachment (*Basement membrane* = connective tissue) 5) Regeneration - Epithelia are replaced by division of *stem cells* near *basal lamina*

CCQ: What are ways in which a muscle cramp can be created? a) Suggest how damage can create cramping. b) Suggest how neural activity can create cramping. c) Suggest how ionic imbalance/dehydration can create cramping (theoretically).

a) Damage - Taxes resources, diverts them to repair rather than making ATP = crossbridges not broken b) Neural activity continues past point of ATP depletion c) Inadequate resources to make sufficient ATP (or too much Ca++, leading to depletion due to sheer numbers) ...

2.What are the components of the cutaneous membrane? a.What specifically is the epidermis (ie: is it simple cuboidal epi...)? b.What is the hypodermis? (what types of tissues?)

a) Epidermis is stratified squamous Dermis lies between them b) Hypodermis (aka subcutaneous layer or superficial fascia) - STabilizes the skin, allows for separate movement - Areolar and adipose tissue (CT) - Vascularized (Blood vessels)

2.About hormones: a. Where are they formed and how do they get to their target cells? b. What, generally, do hormones do? c.Are all hormones chemically the same - yes or no will do here. i. What are two broad categories? d. Can any hormone interact with just any cell? What is required for interaction?

a) They are formed in glands (endocrine = release their contents into blood) - Exocrine cells don't use hormones, and excrete onto epithelial surfaces b) They cause a change in target cell activity (?) c) No ci) Fat soluble and water soluble d) Hormone receptors are highly specific. Only targets that have the exact receptor can be affected - Can be inside or outside target

Study Qs: a. In a single person, do all cells have the same DNA? Which ones are different? Why is this so? b. What molecules does your DNA code for (proteins, carbohydrates, or lipids)? c. How does the nucleus determine cell function? d. What other organelles are used in protein formation other than the nucleus?

a. All cells, except the reproductive cells, have the same DNA (reproductive cells have half so they can fuse to make a new beast) b. They code for proteins (DNA > translation > RNA > transcription > proteins) c. The nucleus determines cell function by deciding which proteins are expressed/transcripted d. Golgi apparatus, rough ER, ribosomes, vesicles

Clinical correlation question: Cells of the body have membrane bound receptors on their surface. These receptors are made of proteins produced by the cell and inserted into the cell membrane. When specific substances bind to their specific receptors, the cell's activity changes (perhaps the cell then starts making a product for secretion). a. What organelles might be responsible for producing the membrane-bound receptors? b. What would happen if the organelles were absent or could not make this surface protein? c. Can you think of a disease that might be characterized by such a problem?

a. Free Ribosomes (since the receptors are made of proteins destined to stay in the cell). b. The cell wouldn't be able to change its activity (in the previous example, it wouldn't make serotonin) c. i. Depression (?)

CCQ: There is such thing as "normal" ranges of human heart rate based on age and sex. There are centers in the brain that are responsible for increasing or decreasing heart rate based on certain signals (like signals from the blood vessels or certain hormones), though there is no receptor monitoring heart rate specifically. Which would have a wider range of "normal" values: heart rate or blood osmolarity? Why?

a. I think that heart rate has a wide range of normal values, because there are a lot of normal situations where heart rate can change (ex. Exercise, excitement, meditation). HR also isn't homestatically regulated (Strictly)

CCQ: Blood salt concentration (osmolarity) is important to overall health. There is a specific receptor in the brain monitoring blood osmolarity, a region of the brain that interprets the levels and a specific hormone released that then affects kidney function to change blood osmolarity. Given all this, is blood osmolarity homeostatically regulated? What would happen if the receptor were damaged? What would happen if the hormone could not bind to its receptors and affect kidney function?

a. It is homeostatically regulated. It has all the components of a homeostatic system, and serves to maintain things in safe ranges. If the receptor was damaged, the system would be unable to sense changes and thus not respond when changes occurred. b. If the hormone couldn't bind to receptors, all of the previous steps would occur, but change would still not happen (as the actual execution wouldn't be possible).

CCQ: 1. Cells of the body have membrane bound receptors on their surface. These receptors are made of proteins produced by the cell and inserted into the cell membrane. a. What organelles would be responsible for producing the membrane-bound receptors? b. What would be a consequence of not producing these membrane-bound receptors in a cell that should produce them?

a. Nucleus > rough ER > Golgi apparatus > vesicles b. They wouldn't be able to detect whatever activates them, and so the cell couldn't change in response to the appropriate stimulus

Study Q: What is the relationship between the number of membrane channels/carriers and the cell's permeability to certain substances?

a. The more membrane channels/carriers there are, the greater the permeability.

CCQ: Cancer cells almost always have a rich blood supply. Why? What other characteristics would you expect of cancerous cells (ie: what organelles present)?

a. They are constantly growing, so if they don't have a rich blood supply (oxygen), they won't be able to sustain themselves. I expect that they'd have lots of mitochondria, and possibly the protein synthesis chain for the cell (free ribosomes)

STudy Q: You observe a population of cells with no mitochondria. Do they produce ATP? How?

a. They have to be, because all cells require energy. Likely through glycolysis or anaerobic respiration (in cytoplasm) b. If it had a lot of mitochondria, it may make ATP aerobically *ATP cannot be stored* - MAde on demand

b.What are the functions of epithelial tissue? c.Where, generally, are epithelia found? To be an effective barrier, an epithelium must form a complete surface. How is this accomplished? (Think of cell junctions...)

b) Function in protection and permeability --------------------------- c) Generally found on all inner and outer body linings (including organs) Cell junctions make it so that epithelium can form a complete covering Two types (know this!) 1) Tight junctions (zipper) - Nothing can pass adjacent cells (ex. GI tract) 2) Desmosome (button) - Looser, allows passage - Ex. on surface epidermis - Multiple layers. Some can be peeled of (Ex. sunburn), bc of this junction

d.What is the function of microvilli on certain epithelial cells? For example, in the gut where substances must be transported across the gut cells to enter the blood stream, there are abundant microvilli. Why? How is this different than the function of cilia in the windpipe?

d) Microvilli increase surface area and aid with absorption/secretion, which is why they're in places where nutrients need to be absorbed. Cillia serve to move substances across epithelial cells.

Study Q: e. What factors determine the rate of transport of fat soluble or water soluble molecules across the cell membrane? If you were to draw them as a graph, how would you depict rates of diffusion across the cell membrane for water and fat soluble molecules as a function of (a) concentration gradient across the cell membrane, (b) temperature, (c) solubility in the cell membrane.

e. Size of molecule, type of transport, steepness of concentration gradient, charge of molecule (water soluble have a limit due to protein channel capacity) ------------------------ (draw a graph - Rate of diffusion (y axis) vs. variable (x axis)) a) Concentration gradient (both go up, but water soluble molecules plateau due to protein carriers) b. Temprature (both go up because particle movement increases) c. Solubility in the cell membrane would increase the rates of diffusion, because they can pass freely through if they're soluble, and thus not subject to carrier limits (although it may matter more at higher concentrations)

CCQ: 2. If I tell you that the pancreas is responsible for producing digestive system enzymes that are released from pancreatic cells to the digestive tract during eating, what organelles would you expect these cells of the pancreas to have?

i. Definitely lysosomes. Probably also vesicles for transport. - Less specific to function would be nuclei, mitochondria, rough ER (since enzymes are proteins), golgi apparatus, and microvilli for secretion