Exam 1 Quiz 1 Flashcards
Define anatomy and physiology and describe their subdivisions
Anatomy: form
what is it?
-scientific name
-location
-relation to other structures
-association with other structures
Physiology: Function
-what does it do?
-how does it do it?
-how does it affect other organs, structures
-what regulates it’s action/function
Explain the principle of complementarity.
anatomy and physiology are inseparable
-function almost always reflects structure
-structure dictates function: selective optimization
form dictating function
think of how the front teeth are shaped and how they are made to bite and molars (back teeth) are made to chew
Name the different levels of structural organization that make up the human body, and
explain their relationships
atoms–> molecules–> organells–> cells–> tissues–> organ–> organ system
organ system interrelationships
-organs require other organs
-organ systems work synergistically in order to function optimally
-cells require organs
Define homeostasis and explain its significance
-maintenance of relatively stable internal environment despite continuous outside changes
-a dynamic state of equilibrium
-happy place of the body
what do homeostatic control mechanisms involve
-Involve continuous monitoring and regulation of many factors (variables)
-Nervous and endocrine systems accomplish the communication via nerve impulses and hormones
physiological stress response
-heart races
-glucose levels rise
-pupil dilates
-digestion stops
- autonomic nervous system (sympathetic nervous system)
homeostatic control mechanisms (mammals)
-for most mammals stress is straight forward
-acute physical stressor results=predictable disturbance of homeostasis
-manage dynamic external environment by modulating internal environment appropriately
-evolutionarily conserved adaptive process
Describe the relationship between homeostatic imbalance and disease
-stress has negative consequences when we stop acting like most other mammals and do not return to homeostasis
-humans get chronically psychogically stressed (this causes us to be constatly out of our normal range)
-BP, blood sugar and heart rate
how does stress impact homeostasis and our immune system
it makes our Bp, blood sugar and heart rate be out of the normal range
we deplete our resources which makes us get sick if we are constatly stressed
can lead to chronic illnes like obesity, diabetes
Homeostatic Control Mechanisms (fight or flight)
beneficial to have fight/ flight response prepare our bodies for impending injury/ infection
-harmful to not return to our resting homeostatic state
Describe how negative feedback maintain body homeostasis
-negative feedback reduces of shuts off the original stimulus
-response of the effector is in opposite direction of stimulus
give examples what negative feed back regulates
-stress hormones (endocrine system)
-body temperature (nervous system)
-blood volume by ADH (endocrine system)
give an example of negative feedback loop in relation to regulating temperature
answer here
talk about negative feed back when regulating blood volume ADH
-receptors sense decreased blood volume
-control center in hypothalamus stimulates pituitary gland to release antidiuretic hormone (ADH)
-ADH is the hormone that stops urination
-ADH causes the kidneys (effectors) to return more water to blood
Describe how positive feedback maintain body homeostasis
-the response enhances or exaggerates original stimulus
-may exhibit a cascade or amplifying effect
-usually controls infrequent events such as the enhancement of labor contraction by oxytocin and platelet plug formation and blood clotting
give an example of the positive feed back loop in relation to temperature
-stimulus: body temperature falls
-receptors: thermoreceptors
information is sent along the afferent pathway to the control center
the control center send the info along the efferent pathway to effectors
effectors: skeletal muscles
response: body temperature rises because shivering begins an the stimulus ends
homeostatic imbalance (hint: aging and death)
-disturbance of homeostasis
-increases risk of disease
-contributes to changes associated with aging
-may allow destructive positive feedback mechanisms to take over (like heart failure)
what is a adaptive disturbance
the fight or flight response
what is maladaptive disturbance
being chronically stressed and getting a chronic illness (diabetes) because of it
Define a cell and explain cell theory.
-the cell is the smallest structural and functional living unit
-organismal functions depend on individual and collective cell functions
-biochemical activities of cells are dictated by their specific subcellular structures
what does a zygote have that a T cell does not
-even though both are cells they are different
-a zygote has the ability to perform functions essential for their own survival as well as specialized tasks to maintain homeostasis depends on successful, cooperative operation of intercellular components
-a zygote is a fertilized egg that have everything it needs to survive
-T cells can recognize infinite number of foreign antigens
Describe the function of the plasma membrane, cytoplasm and the nucleus
-plasma membrane: protects the cell an gives it shape
-cytoplasm: where the organelles are floating
-nucleus: what controls the cell and houses the DNA
what role does membrane transport and membrane potential have in a cell
-these are vital for maintaining homeostasis in a variety of cell types
what is the plasma membrane and what are its functions
-biomolecular layer of lipids and proteins in a constantly changing fluid mosaic
-proteins help with the transit
-plays a dynamic role in cellular activity
-separates intracellular fluid (ICF) from extracellular fluid (ECF)
-ensures different environment inside and outside the cells
Describe the chemical composition of the plasma membrane
75% phospholipids (lipd bilayer)
-phosphate heads: polar and hydrophilic
-fatty acid tails: nonpolar and hydrophobic
5% glycolipids- lipids with polar sugar groups on outer membrane surface
20% cholesterol: affects membrane stability and fluidity
-anchors it
what is the plasma membrane largely made up of
lipids (fat)
are natural steroid hormones lipids why or why not
yes bc they are synthesized from cholesterol
-they can pass through the membrane with out problem
integral proteins and their functions
firmly inserted into the membrane (most are transmembrane)
-transport proteins (channels carrier), enzymes, or receptors
peripheral proteins and their function
-loosely attached to integral proteins
-found on intracellular and extracellular surfaces
-functions include: enzymes, motor proteins, cell- to- cell links, provide support on intracellular surface
6 functions of membrane proteins
- transport
- receptor for signal transduction
- attachment to cytoskeleton and extracellular matrix
- enzymatic activity
- intercellular joining
- cell- cell recognition
how do membrane proteins transport substances
-can provide a hydrophilic channel across the membrane that is selective for a particular solute
-some transports proteins made ATP as an energy sources to pump substances across the membrane (this is when the substance is going against the concentration gradient)
How are membrane proteins receptors
-membrane proteins that are exposed to the outside of the cell may have a binding site with a specific shape that fits the shape of a chemical messenger (like a hormone)
-the external signal may cause a change in shape in the proteins that initiates a chain of chemicals reactions in the cell
Membrane proteins: attachment sites
-attach to the cytoskeleton and the extracellular matrix
-elements of the -cytoskeleton (supports the inside of the cells) and the extracellular matrix may be anchored to membrane proteins, which help maintain the cell shape and fix the location of certain membrane proteins
-others play a role in a cell movement or bind adjacent cells together
enzymatic activity
-A protein built into the membrane may be an enzyme with active site exposed
-in some cases several enzymes in a membrane act as a team that catalyzes sequential steps of a metabolic pathway as indicated
intercellular joining (remember CAMS)
The function of membrane proteins in which membrane proteins of adjacent cells hook together, as in gap junctions or tight junctions (or various intercellular junctions
-some membrane proteins (CAMS or cell adhesion molecules) of this group provide temporary binding sites that guide cell migration and other cell to cell interactions
cell-cell recognition
The function of membrane proteins in which some glycoproteins serve as ID tags that are recognized by membrane proteins of other cells.
-think of how a sperm cell recognizes an egg
membrane transport (think about what the plasma membrane is)
-Plasma membranes are selectively permeable
-Some molecules easily pass through the membrane; others do not
how do molecules pass through a membrane
via proteins
-hydrophilic doorway
what are the types of membrane transport
passive processes and active processes
what are passive processes
-requires no cellular energy (ATP) required bc molecule uses kinetic energy from the concentration gradient itself
-substances moves down its concentration gradient (high to low)
-no resistance
what are active processes
-goes against the concentration gradient
-energy (ATP) is required
-occurs only in living cell membranes
what are the components of a control mechanism
stimulus, receptor, input (send info along an afferent pathway to the control center), control center, output (info gets send along an efferent pathway to effector), effector, response
Compare and contrast simple diffusion, facilitated diffusion, and osmosis relative to substances transported, direction, and mechanism
-all of these are passive processes
-for simple diffusion the molecule needs no help moving across the membrane
-carrier mediated and channel mediated diffusion are both facilitated diffusion (this is when a hydrophilic molecule goes through a hydrophilic protein)
-osmosis is the movement of water across a semi permeable membrane. the goal is to equalize the solute concentration
What is simple diffusion?
-is a passive processes
-when non polar lipid soluble (hydrophobic) substances diffuse directly through phospholipid bilayer
-oxygen, Co2 and Urea (all of these are lipid soluble
What is facilitated diffusion?
-carrier mediated and channel mediated are both facilitated diffusion
-when certain lipophobic molecules (glucose, amino acids and ions) use carrier proteins or channel proteins
-both channel proteins and carrier proteins exhibit specificity (this means that the proteins match the shape or charge of specific molecule
-they are saturable and the rate is determined by number of carrier or channels
-they can be regulated in terms of activity and quantity (this means that we can generate more proteins)
what is the difference between carrier proteins and channel proteins
-carrier proteins have a weird shape and channel proteins are just a straights line they look like a straw
-there are also two types of channels
what are the two types of channel proteins
leakage channels (always open) and gated channels (controlled by chemicals or electrical signals or mechanical signals)
what is the channel proteins that the water passes through during osmosis
Aquaporin and this channel allows water to pass effectively
osmolarity and in what direction do solutes move from
measure of total concentration of solute particles
-high concentration to low concentration
why does osmosis happen
when solutions of different osmolarity occurs until equilibrium is reached
what is water concentration determined by
solute concentration because solute particles displace water molecules
what is importance of osmosis
When osmosis occurs, water enters or leaves a cell
Change in cell volume disrupts cell function/ shape
-this can kill the cell or blow it up
What is tonicity?
the ability of a solution to cause a cell to shrink or swell (which changes the cell volume)
what are the different solutions and what do they entail
-isotonic: solution with same solute concentration as cytosol
-hypertonic: solution with greater solute concentration than cytosol (the cell shrinks)
hypotonic: solution with less solute concentration then cytosol (the cell blows up)
how do you fix an extreme hypertonic case
-the water is being drawn out so we need to administer the hypotonic solution
how do you fix an extreme hypotonic case
-since water is fill up the cell we have to administer a hypertonic solution
what are the determinants of passive movement
-lipid solubility of substance
-channels of appropriate size (if molecule is hydrophilic)
-carrier proteins
what are the two types of active processes
active transport and vesicular transport
what is active transport
-requires carrier proteins (these receive phosphate from the ATP when it breaks one of the bonds)
-moves solutes against a concentration gradient
primary active transport
primary active transport: energy from hydrolysis of ATP causes shape change in transport proteins so that bound solutes (ions) are pumped across the membrane
sodium-potasium pump
ATPase: enzyme
-in all plasma membranes
involved in primary and secondary active transport nutrients and ions
-maintains electrochemical gradients essential for functions of muscle and nerve tissues
-contributes to cell volume bc water follows sodium
what is secondary active transport?
-depends on an ion gradient created by primary active transport
-use kinetic energy to pull another molecule with it
-energy stores in ionic gradients s used indirectly to drive transport of other solutes
what is cotransport, the symport and the antiport system
-these are both apart of secondary active transport
-cotransport: always transports more than one substance at a time
Symport system: two substances transported in the same direction
Antiport system: two substances transported in opposite directions
-still a cotransporter
-uses the energy of sodium concentration gradient
What is vesicular transport?
-the second type of actives processes
-transport of large particles, macromolecules, and fluids across plasma membranes
-requires cellular energy (ATP)–> this is why it is considered active transport
what are the functions of vesicular transport and what is substance (vesicular) trafficking
-exocytosis: transport out of the cell
-endocytosis: transport into cell
-transcytosis: transport into, across and then out of the cell
Substance (vesicular) trafficking: transports from one area or organelle in cell to another
how can molecules move passively across the membrane
-if there is a pathway
-driving force (electrochemical gradient )
The ICF vs the ECF electrochemical potential energy difference acting on solute
what does the potential energy difference of the electrochemical gradient include?
-the electrochemical potential energy difference includes:
concentration gradient of a solute (chemical potential energy difference)
-electrical gradient of charged solute: (electrical potential energy difference): difference in voltage between compartments
what are the principles of electricity
-opposite charges attract each other
-energy is required to separate opposite charges across a membrane
-energy is liberated when the charges move towards one another
-if opposite charges are separated the system has potential energy
-ions are charged/ polarized
-anions are negative charge and cations are a positive charge
Voltage (V)
-measure of potential energy generated by separated charge
potential difference
voltage measured between two points (outside of the cell and the inside of the cell)
Current (I)
the flow of electrical charge (ions) between two points
resistance (R)
hindrance to charge flow (provided by the plasma membrane)
Insulator and what makes the insulation
substance with high electrical resistance
-myelin sheath made by the Schwann cells and the oligodendrocytes
conductor
substance with low electrical resistance created by ion channels
electrochemical gradient (hint this is long one and the explanation includes the inside and outside of the cell
-if the concentration of the outside of the cell is higher than the concentration of the inside of the cell then (assuming no voltage difference), the concentration gradient will drive net movement of X across the membrane from outside to inside (high to low)
-if the concentration of the cell is similar to both sides but there is a voltage different the electrical potential on the outside, is not the same as inside, this is voltage difference will drive net movement of X
-the concentration gradient of X and voltage difference across the membrane (electrical gradient) are two determinants of the electrochemical gradient
What is membrane potential?
-separation of oppositely charged particles (ions) across a membrane creates a membrane potential
what is resting Membrane Potential (RMP)
-voltage difference measured in resting state in all cells
-all polarized at rest
-results from diffusion of multiple ions (mainly K+) and active transports of ions
-ranges from -50 to -100 mV
-when talking about the range you are always referring to interior of cell
List the basic functions of the nervous system
sensory input, integration, motor output
Explain the structural and functional divisions of the nervous system(aka what is in each division and what does it do)
Central Nervous System: the brain and the spinal cord (these are the integrative and control centers
Peripheral Nervous System: includes the cranial nerves and spinal nerves
-is in charge of communication lines between the CNS and the rest of the body
Sensory (afferent) division: a subdivision of the peripheral nervous system
-somatic and visceral sensory nerve fibers
-conducts impulses from receptors to the CNS.
-input
Motor (efferent) division: motor nerve fibers
-conducts impulses from the CNS to effector (muscles and glands)
-the outgoing part
Somatic nervous system: somatic motor (voluntary)
-conducts impulses from the CNS to skeletal muscles
-subdivision of the motor division
Autonomic Nervous system: second subdivision of the motor division
-visceral motor (involuntary)
-conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands
Sympathetic division: subdivision of the ANS
-mobilizes body
-system during activity
Parasympathetic division: conserves energy
-promotes house keeping functions during rest
-second division of the ANS
Define neuron, describe its important structural components, and relate each to a functional role
-excitable cells that transmit electrical signals
-functions are afferent/ sensory
-efferent/ motor
-interneurons
structural classifications: multipolar
-many dendrites (aka processes)
-unipolar (one dendrite)
bipolar ( 2 processes)
List the types of neuroglia and cite their functions
-aka glial cells
-supporting cells for the neuron
-astrocytes (CNS)
-microglia(CNS)
-ependymal cells (CNS)
-oligodendrocytes (CNS) (focus on knowing this one)
-satellite cells (PNS)
-Schwann cells (PNS) (focus on knowing this one)
what does depolarization of the membrane above a certain threshold voltage do?
triggers an action potential
what does the conduction of the action potential do and what can action potentials trigger
information to be transmitted
-action potentials may trigger neurotransmitters release
explain the concentration of Na and K in relation to resting membrane potential
-the ICF has lower concentration of Na and Cl- than ECF
-ICF has higher concentration of K+ and negatively charged proteins (A- or anions) than ECF
-impermeable to A-
-slightly permeable to Na+ (for leakage ICs)
-75-100 times more permeable to K+ (more leakage ICs)
-Freely permeable to Cl-
explain the generation and maintenance of the resting membrane potential
-some k+ continually diffuses down it’s concentration gradient out of cell through K+ leakage channels
-membrane interior becomes negative (relative to exterior) due to K+ leaking out and large anions trapped inside cell
-electrochemical gradient begins to attract K+ back into cell
-greater driving force for Na+ to leak into cell (equilibrium for Na is +40)
-RMP is established at point where ion movement is minimized and is much closer to Ek+ (equilibrium of potassium) because membrane is far more permeable to K+
-the sodium potassium pump continuously ejects 3 sodium from the cell and carries potassium back in
-steady state is maintained bc rate of active transports off sets ion movement through leakage channels
depolarization and repolarization
Na and K (in the case of the example that we used)rushes into the cell, cell becomes more positive
Repolarization
Na+ channels are inactivating, and K+ channels open
-K+ can leave which means that the inside of the cell is getting more negative
-pushes membrane potential towards -70 MV
Hyperpolarization
membrane potential becomes more negative
gated channels and voltage gated channels
-there are two types
-Gated channels/ ligand gated channels: chemically gated (ligand- gated) channels), open via binding of specific neurotransmitter
Voltage- gated channels: open and close in response to changes in membrane potential
-access the hillock and axon
what is a ligand
substance that is able to bind to and form a complex with a biomolecule to serve a biological purpose
-can be a chemical or a neurotransmitter
what happens when gated channels are opened
-ions diffuse quickly across membrane along their electrochemical gradients
-this means that ions flow towards the equilibrium potential
-ion flow creates an electrical current that changes voltage (membrane potential)
What causes a graded potential and how long to graded potentials last?
-a stimulus causes the gated ion channels to open
-the magnitude of graded potentials vary directly with stimulus strengths
-they are short distance signals along dendrite/ soma
what happens when an excitatory neurotransmitter interacts with its receptors
-remember specificity
-sodium channel opens, this causes Na to rush into (this is the graded potential)
-the inside of the cell becomes less negative (this causes it to be somewhat depolarized)
-over time the channel will close
-excitatory graded potential caused depolarization and inhibitory graded potential causes hyperpolarization
Initiating an excitatory signal for graded potentials
-Na+ ions begin to spread, two dimensionally running along inside of membrane, attracted by the negative environment in front of them
-an excitatory signal dissipated (electronitc decay)
-eventually all of those Na+ ions are umped back out, returning to RMP
-thus graded potentials are generated and then decay
Summation
no single dendrite getting depolarized by an excitatory neurotransmitters is going to make enough of a ripple to reach the axon hillock
-integration/ summation is necessary for AP
spatial summation
-lots of dendrites getting depolarized all at once
-dendrites firing on dendritic tree
Temporal summation
-a few depolarized over and over
-frequency of stimulus, few neurons firing repeatedly but in the same spot
what is the big picture of action potential
-ligand- gated channels and voltage gated channels
-if graded potentials is big enough at axon hillock, it will depolarize are past threshold
-voltage gated channels open Na+ rushes in -open if threshold is reached
-if we don’t reach the threshold we don’t get an Action potential
What is an action potential?
-Na influx depolarizes whole region, causing next voltage- gated channel to open… which causes the next one…
-explosive, regenerative pattern of depolarization shooting down length of axon= action potential
-AP continually regenerated 9unlike graded potentials) because of the gated potential’s decay
-abundance of Na+ inside of the neuron around the membrane makes the cell positive (+30)
-demonstrates sharp contract in electrochemical picture from rest to excitation (-70 to +30 mv) shift in polarity
Depolarizing Phase
-depolarizing local current open voltage gated Na+ channels
-Na+ influx causes more depolarization
-t threshold (-55-50 mV) positive feedback leads to opening of all Na+ channels, and a reversal of membrane polarity to +30 mV (spike in membrane potential = (action potential)
-the positive feedback is that the voltage gated channels open over and over again
what happens at threshold
-membrane is depolarized by 15 to 20 mV
-Na+ permeability increases (this means that it’s voltage gated channels open)
-Na+ influx exceeds K+ efflux
-the positive feedback cycle begins results in an AP
what doesn’t reach threshold
-subthreshold stimulus
-weak local depolarization does not reach the threshold
-Ap is an all or nothing phenomenon (they either happen all the way or not at all
repolarizing Phase
-Na+ channel gates close
-membrane permeability to Na+ declines to resting levels
-slow voltage-sensitive K+ gates open
-K+ exits the cell and internal negativity is restored
What is the role of the sodium-potassium pump and repolarization
-restores resting electrical conditions of neuron
-but does not restore the resting ionic conditions
-ionic redistribution back to resting conditions is restored by thousands of sodium potassium pumps
-this allows us to come back from hyperpolarization
absolute refractory period
-Time from opening of Na+ channels until resetting of the channels
-Ensures that each AP is an all-or-none event
-Enforces one-way transmission of nerve impulses
-no opening of channels again until the rest is done
relative refractory period
-follows the absolute refractory period
-most Na+ channels have returned to their resting state
-some K+ channels are still open
-repolarization is occurring
-exceptionally strong stimulus may generate an AP
how do local anesthetics inhibit voltage gated Na+ channels
-prevents nerve impulses like action potentials
-used to control pain
propagation of action potentials
-axon is longest part of a neuron
-neural communication would be slow if an AP had to slowly make its way from Na+ channel to sodium channel down 60 ft of axon
-myelination accelerated movement
-glial cells (Schwan cells) wrap tightly around axon forming myelin sheaths
how do glial cells increase resistance
-nodes of Ranvier
-saltatory conduction
-reduces capacitance across membrane, and thus AP moves more quickly
-nodes of Ranvier are gaps allowing new channels to open (to regenerate the AP)
-Ap rapidly jumps from one node to node (this is a saltatory conduction)
-most of the nervous system is not myelinated when we are born process occurs gradually
multiple sclerosis
-autoimmune disease mainly affecting young adults
-symptoms are: visual disturbances, weakness, loss of muscular control, speech disturbances, and urinary incontinence
-myelin sheath in CNS deteriorate and become nonfunctional scleroses
-shunting and short circuiting of nerve impulses occurs
-impulse condition slows and eventually ceases
The synapse, presynaptic neuron and, postsynaptic neuron
-junction that mediates information transfer from one neuron to another neuron or effector cell
-presynaptic neuron- releases neurotransmitter, conducts impulses towards synapse
postsynaptic neuron- transmits impulses away from synapse
information transfer
-AP arrives at axon terminal of the presynaptic neuron and opens voltage-gated Ca2+ channels
-Synaptotagmin protein binds Ca2+ and promotes fusion of synaptic vesicles with axon membrane
-Exocytosis of neurotransmitter occurs
-Neurotransmitter diffuses across synaptic cleft and binds to receptors (often chemically gated ion channels) on the postsynaptic neuron
-Ion channels are opened, causing an excitatory or inhibitory event (graded potential)
Termination of Neurotransmitter Effects
Within a few milliseconds, the neurotransmitter effect is terminated
-Degradation by enzymes
-Reuptake by astrocytes or axon terminal
-Diffusion away from the synaptic cleft
Excitatory Synapses and EPSPs
-Neurotransmitter binds to and opens chemically gated channels that allow simultaneous flow of Na+ and K+ in opposite directions
-Na+ influx is greater that K+ efflux, causing a net depolarization
-EPSP helps trigger AP at axon hillock if EPSP is of threshold strength and opens the voltage-gated channels
inhibitory synapse and IPSP
-neurotransmitter binds to and opens channels for K+ or Cl+
-causes hyperpolarization (inner surface of membrane becomes more negative)
-reduced postsynaptic neuron’s ability to produce AP
