Principles of Physiology Exam 1

0.0(0)
studied byStudied by 176 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/88

encourage image

There's no tags or description

Looks like no tags are added yet.

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

89 Terms

1
New cards
Krogh's principle
for every biological problem there is an organism on which it can be most conveniently studied
2
New cards
Bergman's rule
larger species will be found in colder climates; species of smaller sizes will be found in warmer climates
3
New cards
Body Size and Complexity
complexity increases with body size to increase internal surface area ratio
4
New cards
Basal Metabolic Rate (BMR)
metabolic rate when organism is at rest (energy needed for vital processes)
5
New cards
Mass-Specific Metabolic Rate (MSMR)
BMR divided by organism's mass
6
New cards
BMR vs Mass
allometric relationship- nonlinear correspondence between BMR and mass
7
New cards
Surface Area and Volume
SA:V ratio gets smaller as volume increases at much faster rate than surface area; having more SA means higher rate of exchange across cell membrane
8
New cards
Pros and Cons of being large
Pros: maintains body temp more easily, have more inert tissue, greater cell specialization
Cons: move slower, more easily targeted by predators, require carefully maintained environment
9
New cards
Homeostasis
maintained via negative feedback loops; equilibrium state
10
New cards
Conformers
organisms where homeostasis is heavily influenced by environment
11
New cards
Avoiders
organism where homeostasis avoid environmental conditions
12
New cards
Regulators
organisms where homeostasis is mid affected
13
New cards
Negative Feedback Loops
Give signals to return to systems to norman/baseline, most common, lots of subtypes
Antagonistic: usually to effectors with opposite effects
Anticipatory: activates corrective response before variable is disturbed (ex. glucose and insulin, thermostat, body temperature)
14
New cards
Feedback Loop terms
Stimulus: initiation event
Variable: effect
Sensor: detects the change in the variable
Integrator: compares against reference value (set point)
Effectors: make adjustments to the variable
15
New cards
Positive Feedback Loops
work to enhance or continue change, rare
(ex. labor, fight and flight)
16
New cards
Nucleotides
DNA/RNA, ATP/NADH
DNA/RNA Structure: phosphate group, pentose sugar (deoxyribose), nitrogenous base
ATP: 3 phosphate groups, adenine, ribose
NADH: same thing lol
17
New cards
Proteins
Functional: enzymes, transport, channels
Signaling: millions of signaling molecules and receptors
Immunity: antibodies
Energy storage: protein catabolism
Structural: microtubules and other filaments
20 different amino acids: categorized into polar charges, polar uncharged, nonpolar (hydrophobic)
18
New cards
Levels of Protein Structure
Primary: sequence of amino acids
Secondary: hydrogen bonds, alpha helices, beta sheets
Tertiary: noncovalent bonds, just folding
Quaternary: multiple subunits together
19
New cards
Heat Shock and Protein Damage
Proteins unfold/misfold at high temperatures
Heat shock-proteins interact with other proteins to help them fold correctly
20
New cards
Carbohydrates
Sugars in single units or chain
Energy Storage (glucose): packed together and stored as starch or glycogen
Structural (cellulose chitin)
Signaling (glycoproteins glycolipids): cell adhesion and recognition (ABO blood types), digestion (absorptive surface)
21
New cards
Lipids
Fatty acids, triglycerides, phospholipids, cholesterol
All are hydrophobic: nonpolar C-H bonds, need help travelling through blood
Energy storage: long-term storage (fatty acids, triglycerides)
Structural/functional (cell membranes)
Has to be transported as triglyceride (glycerol plus fatty acids)
Saturated vs Unsaturated fatty acids
Structure of phospholipids: polar head face out and nonpolar fatty acid tails face inward
Steroids: derived from cholesterol through a series of enzymatic modifications, easily diffuse across cell membranes to bind to intracellular receptors
22
New cards
Central Dogma
Allele of gene transcribed into RNA containing exons and introns that go through exon splicing to get mRNA that is translated into a protein by a ribosome and tRNA
23
New cards
Glycolysis
1. spend 1 ATP to trap glucose in the cell (hexokinase takes glucose and makes glucose 6-phosphate)
2. rearrange it to prepare for split
3. spend 1 ATP add a P prepare split
4. splits into 3 carbon molecules [glyceraldehyde-3-phosphate]
5. interacts NAD + Pi to create NADH + H+ to add extra phosphate G-3-P (2x)
6. two P groups transferred to ADP to make 2 ATP (2x) -> 2 pyruvate
24
New cards
Input and Output of Glycolysis
Input: 2 ATP, glucose, NADPi
Output: 4 ATP, 2 pyruvate, 2 NADH, H2O
Net ATP: 2
25
New cards
Linking Step
Pyruvate to Acetate
1. move pyruvate from cytosol to mitochondria (gain NADH, convert pyruvate to Acetyl-CoA)
2. pyruvate travels through transmembrane protein, releases CO2, protonate an NAD to NADH, and is tagged with Coenzyme A to produce Acetyl-CoA
26
New cards
Citric Acid/Krebs Cycle
1. Acetyl-CoA combines with oxaloacetate and water via Citrate synthase to create Citrate and CoA-SH (makes the 3 C Acetyl-CoA a 6 C Citrate)
2. Energy-harvesting steps produce: 3 NADH + FADH2 + ATP (2x) (so in total- 6, 2, 2)
3. overall by this point, 1 glucose molecule has produced: 4 ATP, 10 NADH, 2 FADH2
27
New cards
Anaerobic Respiration
Begins with glycolysis, but pyruvate interacts with lactate dehydrogenase to convert it into lactate; makes less energy but at a faster pace
28
New cards
Electron Transport Chain (Oxidative Phosphorylation)
1. 10 NADH * 2.5 ATP = 25 ATP
2. 2 FADH2 * 1.5 ATP = 3 ATP
Net 28 ATP
- proton gradient has high extracellular proton concentration and low intracellular proton concentration; gradient drives ATP synthase
- waste products: oxygen free radicals (oxygen containing unpaired electrons) search for electron to complete and stabilize atom (can be combated via antioxidants)
29
New cards
Where does each step of glucose metabolism take place?
1. glycolysis = cytosol
2. linking step = mitochondrial matrix
3. krebs cycle = mitochondrial matrix
4. ETC = mitochondrial inner membrane
30
New cards
Free Radicals
contain an unpaired electron
31
New cards
Antioxidant
can donate a spare electron
32
New cards
Fat Catabolism
1. Lipolysis: triglycerides broken down into free fatty acids
2. transported into mitochondria- use 2 ATP and CoA to make a fatty Acyl-CoA (activated fatty acid)
3. carnitine replaces CoA so that it can help long-chain fatty acids across mitochondrial membrane (short chains can cross alone)
4. Beta Oxidation: snips off two carbon atoms at a time and sends Acetyl-CoA to citric acid cycle
33
New cards
Protein Catabolism
1. Proteasomes digest chains tagged with ubiquitin
2. newly broken amino acids can go directly into Krebs cycle
- glucogenic, ketogenic, and glucogenic/ketogenic
34
New cards
Nucleic Acid Catabolism
1. glycolysis breaks nucleotides into nucleoside, then separates pentose and base along glycosidic bond
2. purines turn into uric acid
3. pyrimidines turn into citric acid cycle intermediates
35
New cards
Fluid Mosaic
- cell membranes are never static
- CM composed of phospholipid bilayer (hydrophilic head and hydrophobic tail)
- Saturated (no double/triple bonds) v Unsaturated (has "kinks" created by double/triple bonds)
- Membrane fluidity: liquid crystal at high temp, crystal at low temp (can't function properly)
- Fluidity maintained by cholesterol levels and unsaturated fatty acids
36
New cards
Selective Permeability
- Permeable: gasses and lipophilic molecules
- Semipermeable: small uncharged polar molecules
- Impermeable: large uncharged polar molecules, ions
37
New cards
Simple Diffusion
- movement of particles from high to low concentrations without protein, no energy or transporters needed, applies to lipid-soluble molecules, driven by concentration gradient
- Fick's Law: "molar flux due to diffusion is proportional to the concentration gradient"
-Osmosis
38
New cards
Osmosis
-movement of a solvent through a semipermeable membrane to equalize the solute concentration (solvent typically water and solute is molecule)
39
New cards
Osmotic Pressure
- force that must be applied to a solution side to stop movement of water
- hypoosmotic: low osmotic pressure, low # of solutes in cell, water diffuses out
- hyperosmotic: high osmotic pressure, high # of solutes in cell, water diffuses in
- isosmotic: equal osmotic pressure, equal number of solutes, no net movement of water
40
New cards
Osmolarity
a measure of osmotic pressure of a given solution (unit = osmoles)
41
New cards
Tonicity
- same measure as osmolarity BUT only applies to non-permeable solutes; penetrating solutes have NO effect on tonicity
- hypertonic solution has a higher concentration of solutes outside the cell, water leaves and cell shrinks (plasmolysis)
- hypotonic solution has a lower concentration of solutes outside the cell, water rushes in and cell expands (cytolysis)
- isotonic solution has equal concentration outside cell, no net movement of water
42
New cards
Facilitated Diffusion
- no ATP required, moves down concentration gradient, requires carrier protein (channel)
- open channels: allows only select molecule to flow through freely
- gated channels: can open/close in response to various stimuli (voltage, ligand, mechanical)
- carrier proteins allow molecules through via conformational change; types are uniport, symport, and antiport
43
New cards
Active Transport
- protein transporter needed, energy is required, molecule moves against concentration gradient
- primary active transport: uses ATP directly (ex. Na+/K+ ATPase pump)
- secondary active transport: uses ATP indirectly, couples movement of one molecule to movement of second molecule; can take product of one primary AT and use it in secondary AT
44
New cards
Cell Signaling Basics
- Signaling cells: send a signal
- Target cells: receives the signal
45
New cards
Indirect (local and distant) signaling
1. release of chemical messenger from signaling cell
2. transport of messenger to target cell
3. communication of signal to target cell
46
New cards
Water and Lipid Solubility
- Hydrophobic and lipophilic: not water soluble, dissolves in lipids, ex. steroids, can't be stored, need carrier proteins, can diffuse across cell membrane
- Hydrophilic and lipophobic: water soluble, does not dissolve in lipid, ex. proteins, can be stored in vesicles, travels freely in blood, can't cross cell membrane but utilizes surface receptors
47
New cards
Ligand-receptor interactions
- Specificity: receptors bind to only correct shaped ligands
- Agonists: activate receptors
- Antagonists: blocks receptors
48
New cards
Regulation of Response
- can down/up regulate by changing number of receptors on cell (more receptors = more response)
- number of receptors most directly related to intensity of response
- Signal transduction pathways increase (amplify) number of molecules affected
49
New cards
Ligand-Gated ion channels
- ligand binding causes change in receptor shape
- concentration gradient dictates direction
50
New cards
Enzyme-linked receptors
- receptor has single membrane-spanning segment
- intracellular domain has enzymatic activity (ex. tyrosine kinase)
- when ligand binds, catalytic domain starts a cascade of events (ex. phosphorylation)
- MAP Kinase, G-protein coupled receptors
51
New cards
MAP Kinase
- regulates genes involved in cell growth/survival
- abnormal signaling = uncontrolled cell growth (cancer)
52
New cards
G-protein coupled receptors
- protein that spans cell membrane, interacts intracellularly with G-proteins
- contain several membrane spanning segments (domains)
- G-protein named for ability to bind to guanosine nucleotide
- activated second messenger systems
53
New cards
G-protein signaling basics
- composed of alpha, beta, and gamma subunits
- alpha begins inactive with bind to GDP
- ligand binds to receptor, leading to conformational change causing alpha subunit to exchange GDP to GTP
- Alpha dissociates from beta/gamma
- alpha activates downstream enzymes and second messengers
- effector enzyme: targets of G-proteins that produce second messengers
54
New cards
Second Messengers
- (alpha)s stimulates adenylyl cyclase which then catalyzes ATP to cAMP; protein kinase enzymes activated by second messenger and catalyze phosphorylation of other proteins
- (alpha)i inhibits adenylyl cyclase
- (alpha)q stimulates phospholipase C which cleaves PIP2 into diacylglycerol (DAG) and inositol triphosphate (IP3); DAG activates protein kinase C while IP3 binds to calcium channel in ER causing calcium release which activated protein kinase enzymes
55
New cards
Subunit -> Effector Enzyme -> 2nd Messenger
- (alpha)s -> adenylyl cyclase -> cAMP
- (alpha)i -> adenylyl cyclase -> cAMP
- (alpha)q -> phospholipase C -> IP3/calcium & DAG
56
New cards
A cell at rest is ...
- negatively charged (around -70 mV)
- maintained via ion channels and electrochemical gradient
57
New cards
Chemical Gradient
ions flow according to ion concentrations, always high to low
58
New cards
Electrical Gradient
- opposites attract, same repel
59
New cards
Electrical properties of CM
- voltage: separation of charged particles on either side creates potential for electrical flow
- current: the movement of charged particles
60
New cards
Electrochemical gradient
- how cells maintain different ion concentrations inside and outside of cell
- chemical: ions diffuse to lower concentration
- electrical: charges attracted to opposite
- equilibrium potential: equal and opposite, no net flow
61
New cards
Nernst Equation
- calculates voltage necessary to oppose net movement of single ion down concentration gradient
- Ex = (61/z)*log([X] outside/[X] inside)
62
New cards
Goldman Hodgkin Katz (GHK) equation
- calculates equilibrium voltage of membrane with account of all ions
- Em = (61 mV)*log[(Pkout+Pnaout+Pclin)/(Pkin+Pnain+Pclout)]
- potassium has highest permeability (P=1), all others relative to it
63
New cards
Neuron Structures
- Multipolar neuron: many dendritic branches, motor (CNS -> effector), pyramidal, Purkinje
- Bipolar neuron: two main branches, relay (CNS -> CNS)
- Unipolar neuron: one main branch, sensory (receptor -> CNS)
64
New cards
Functional Zones of Neuron
1. signal reception: dendrites and soma; received incoming signals and converts it to change in membrane potential
2. signal integration: axon hillock; signal crosses threshold -> action potential started
3. signal conduction: axon (wrapped in myelin sheath); AP travels down axon, unidirectional
4. signal transmission: axon terminals; neurotransmitters released
65
New cards
Neuron Anatomy
dendrites, cell body (soma), axon hillock, axon, myelin sheath (Schwann cells), synapse
66
New cards
Axon size and conduction speed
- the thicker the diameter of the axon, the faster the potential travels (if get too big, end up becoming limiting)
- the more myelinated the axon is, the faster the potential travels
67
New cards
Myelination
- insulating layer of lipid-rich Schwann cells wrapped around axon of internodes
- glial cells: supportive cells
- nodes of ranvier: areas of exposed axonal membrane
- saltatory conduction: AP leaps from node to node
68
New cards
Membrane potential at rest
- created by electrochemical gradient
- main players: Na+ and K+
- resting MP is -70mV
69
New cards
Membrane potential during an action potential
1. Na+ channels begin to open in reaction to slight positive membrane change, Na+ rushes in cell, more Na+ channels begin to open (keeps going until equilibrium potential of +60mV is reached)
2. Na+ inactivation gates close and K+ channels open, K+ rushes out of cell (keeps going until equilibrium potential of -90mV is reached), excess K+ leaks back out
70
New cards
Action Potential
1. depolarization
2. repolarization
3. hyperpolarization
71
New cards
What affects likelihood of an action potential?
- intensity of initial stimulus
- number and types of stimuli that occur together
- frequency of repeated stimuli
- distance from stimuli to axon
- graded potential
72
New cards
Voltage-gated Na+ channels
- 2 gates: normal gate and inactivation gate
- closed at RMP and opens if threshold potential reached
- inactivation gate begins to close slowly throughout depolarization
73
New cards
Voltage-gated K+ channel
- one gate, stays closed at RMP
- opens slowly once -55 mV reached
- open from peak potential through hyperpolarization
74
New cards
Refractory period
- occurs around hyperpolarization
- absolute: incapable of generating new AP, Na+ channel closes, membrane must repolarize
- relative: more difficult to generate AP but can happen with strong enough signal, some Na+ channels inactive and increased K+ channels open
75
New cards
The Synapse
- signal transmission zone
- synaptic cleft: space between presynaptic and postsynaptic cells
- neuromuscular junction: synapse between a motor neuron and a muscle
76
New cards
Diversity of synaptic transmission
- electrical synapse: common in simple animals, gap junction (direct communication between neurons), fast form of communication, can be bi-directional, postsyn and presyn signal similar, excitatory signals only
- chemical synapse: common in complex animals, slower, unidirectional, postyn signal can be different, excitatory or inhibitory
77
New cards
Neurotransmitter release
1. AP reaches axon terminal and depolarizes membrane
2. voltage-gated Ca2+ channels open and calcium flows
3. calcium influx triggers synaptic vesicles to release neurotransmitter
4. neurotransmitter binds to receptors on target cells; ionotropic channels (ligand gated, neurotransmitter binds directly to channel- ex. glutamate) or metabotropic channels (G-protein coupled, neurotransmitter binds to G-protein which sends intracellular signal messengers to open up channel- ex. GABA)
78
New cards
Types of Transmitters
- inhibitory: cause hyperpolarization, postsynaptic cell less likely to generate AP
- excitatory: cause depolarization, postsynaptic cell more likely to generate AP
- ions: Na+ channels are depolarizing and excitatory, K+ are hyperpolarizing and inhibitory, Cl- are hyperpolarizing and inhibitory
79
New cards
Signal Strength
- influenced by neurotransmitter amount and receptor activity
- release: due to frequency of AP, chich influences Ca2+ concentration
- removal: degradation of synaptic molecules by enzymes, uptake by surrounding cells, or passive diffusion out of synaptic cleft
- receptor activity: density of receptors on postsynaptic cell
80
New cards
Kinesin
- motor protein, serves to move vesicles down the axon and axon terminals
81
New cards
Major Neurotransmitters
- cholinergic (acetylcholine): primarily assc. with parasympathetic NS, neuromuscular junction
- adrenergic (norepinephrine, epinephrine): assc. with sympathetic NS, smooth muscle, heart muscle
82
New cards
Neuromuscular junctions
- specialized synapses
- motor neurons presyn cell with ACh -> postsyn is muscle
83
New cards
Primary cholinergic receptors
- Nicotinic: ion influx, simple ion-gated channel, sodium, excitation, ionotropic
- Muscarinic: excitation and inhibition, g-protein coupled
84
New cards
Adergenic system
- epinephrine and norepinephrine
- neurohormones: can be neurotransmitters at synapses (NE) or travel in blood as hormone (E)
- found in sympathetic NS
- receptors: membrane bound G-protein coupled receptors; have varying affinities for EPI and NOR (beta higher affinity for E, alpha higher affinity for NE)
85
New cards
Common neurotransmitters
adrenaline (E), noradrenaline (NE), acetylcholine (ACh), dopamine, serotonin, glutamate, GABA
86
New cards
Numbers to know
- Resting membrane potential = -70mV
- Eq potential Na+ = +60mV
- Eq potential K+ = -90mV
- Eq potential of Cl- = -65mV
- Eq potential of Ca2+ = +120 mV
- AP threshold = -55 mV
87
New cards
Summation
- EPSP-IPSP Cancellation: excitatory and inhibitory graded potentials cancel each other out
- Spatial Summation: excitatory potentials from many neurons trigger threshold point
- Temporal Summation: many excitatory potentials from one neuron triggers threshold point
88
New cards
Which GPCR alpha subunit does each adrenergic receptor have?
- alpha 1 is Gaq
- alpha 2 is Gai
- alpha B Gas
89
New cards
Tetrodotoxin (TTX)
- binds to and blocks Na+ channels