Fundamentals of Physiology - Exam 1

gap junction

What type of cell communication involves a direct connection between two cells allowing electrical and chemical signals to pass from cell to cell

cardiac muscle

what type of tissue most commonly has gap junctions

contact dependent signals

what type of cellular communication has interaction between the membranes of cells causing a signal to be released

cell adhesion molecule

what is the receptor in contact dependent signaling called

autocrine signaling

what type of signal involves cellular release of chemicals in response to itself

paracrine signaling

what type of signal involves secretion of a cell that affects other cells within the local area

interstitial fluid

rapid

paracrine signling involves diffusion through ___________ _______ and elicits a ___________ response

distance

what is a limiting factor for paracrine signaling

long distance communication

what type of cellular communication can occur with electrical and chemical signals that travel long distances with effects on distant targets

neurotransmitters

a long distance signal created by an axon involves an action potential triggering the release of _______________ from the axon terminal to the target receptors

blood stream

hormones secreted into the _________ _________ participate in long distant communication to target cells

neurohormones

what chemical messenger is made by specialized nerve cells

neuro-secretory cells

what type of cell creates neurohormones

there will be no response

what will happen when hormones are released in the blood and organs/cells don't have a receptor

ligand (molecule that binds to target)

in the signaling pathway, what is the first messenger

ligand binding to receptor

what causes receptor activation in the cell signaling pathway

a secondary signal within the cell

what is the effect of the ligand/first messenger binding to the receptor

proteins that cause a response

what is the common target of second messengers/intracellular signals

cell membrane

intracellular

what are the different types of receptors

cytosol or nucleus

where are intracellular receptors located

diffusion through the cell membrane

how does the ligand/signaling molecule reach intracellular receptors

lipophilic molecules

they can pass through the phospholipid cell membrane

what type of signal molecule will diffuse through the cell membrane and why

slower

gene

intracellular receptor binding results in _________ responses related to changes in _________ activity

rapid

cell membrane receptor binding results in ________ cellular responses

lipophobic molecules

what type of signal molecule will not be able to diffuse through the cell membrane

receptor channels, receptor enzymes, GPCRs, and Integrin receptors

what are the 4 types of extracellular receptors

rapid open/close of channel which changes the cells permeability

when a receptor channel protein is bound to a ligand, what is the response

change in membrane potential resulting in an electrical signal

what is the effect of changing the cell membranes permeability

nerves and muscles

what types of tissues commonly have receptor channels

receptor regions (extracellular)

enzyme region (intracellular)

what are the 2 regions of receptor enzymes

activation of enzymes in the cell causing a response

when the extracellular region of the receptor enzyme is bound, what is the response

GPCR

which type of receptor has a protein that crosses the phospholipid bilayer 7 times with its tail connected to a G protein within the cytoplasm

opening of an ion channel

altered enzymatic activity

activation of GPCRs results in...

proteins in the cellular matrix

ligands (antibodies or blood clotting molecules)

integrin receptors have an extracellular side that binds to...

the cell cytoskeleton via anchor proteins

what is the intracellular side of integrin receptors attached to

blood clotting process

what process uses integrin receptors?

activation of intracellular enzymes

reorganization of the cytoskeleton

binding of a ligand to integrin receptors results in...

signal transduction

what is the term for the process where extracellular molecules activate a membrane receptor and alters intracellular molecules to create a response

turning one signal into multiple second messengers

what is the process of signal amplification

amplifier enzymes

what molecule causes signal amplification via production of the second messenger

cascade

second messenger formation leads to a ___________ effect ultimately resulting in the cellular response

one ligand may have multiple receptors

how can one ligand produce multiple responses

vasoconstriction

epinephrine is a ligand, what is the result of binding alpha-receptor in the GI system

dilation of blood vessels in skeletal muscle

epinephrine is a ligand, what is the result of binding beta-receptor in the MSK system

specificity

the ability of a ligand to bind one type of receptor and not others is known as receptor _____________

competition

receptor ______________ is when different ligand molecules with similar structure compete for a receptor type

saturation

receptor ______________ is when protein activity reaches a maximum rate due to a limited number of receptors

response elicitation

what is an agonistic response to ligand binding

prevention of a response

what is an antagonistic response to ligand binding

an enhanced response

Initially, what occurs with a high concentration of ligand

the body tries to establish homeostasis

what happens over time due to a high concentration of ligand

there is a decrease in the number of receptors

what occurs with down regulation

endocytosis

how does the number of receptors decrease

a quicker cellular response that is easily reversible

what is the result of desensitization

a decrease in ligand concentration

what causes up regulation (increase in number of receptors)

ligand is degraded by enzymes, transported to other cells, or endocytosis of receptor/ligand complex

what are the 3 methods of termination?

bone

voluntary

Skeletal muscle is anchored to ___________ and is under ____________ control

blood

contraction of cardiac muscle propels ___________ through the circulatory system

spontaneous

ANS and hormones

Cardiac muscle can have _____________ contraction and is regulated by...

skeletal and smooth muscle

cardiac muscle combines features of both...

nucleus

cardiac muscle has a single ____________

mitochondria

which organelle is abundant in cardiac muscle

intercalated disks

not every cardiac muscle is innervated, cells transmit electrical signals via...

desmosomes (physical/mechanical connection)

gap junctions (chemical/electrical connection)

what are the components of intercalated discs

between the atria and ventricles

what areas of the heart do not have gap junctions

they consume 70-80% of the oxygen delivered via oxidative phosphorylation with mitochondria (2x more than other cells)

why are heart cells more efficient than other cells?

invaginations in the cardiac muscle

what are T tubules in cardiac muscle

large amounts of calcium

what is released from T tubules

the heart to contract as one unit

connections between cardiac muscle cells allows stimulation of one part of the muscle to be sent across the entire area of muscle tissue, this allows...

resting membrane potential

what represents the separation of electrical charge across the cell membrane

Na+, Cl-, and Ca 2+

which ions are more concentrated outside of the cell

potassium (K+)

which ion is more concentrated in the cytosol

potassium concentration gradient

resting permeability to Na+, K+, and Cl-

Resting membrane potential is determined by...

ion movement across the membrane (from high concentration to low concentration)

changes in concentration gradient and cell permeability leads to...

slightly

at rest, cell membrane is ____________ permeable to Na+

depolarized

an electrical signal (AP)

when there is an increase in cell permeability to Na+ (Na+ flows in), the cell membrane becomes ____________ leading to the creation of...

hyperpolarized (more negative)

if the cell is more permeable to K+ (K+ flows out), the cell membrane becomes _____________

false: there will always be more K+ within the cell and more Na+ outside

true or false: a change in membrane potential means there is more K+ outside the cell and more Na+ within the cell

opening and closing channels

how do cells change permeability

mechanically gated

which type of gated channel will respond to vibration or pressure

chemically gated

which type of gated channel will respond to a ligand

voltage gated channels

what type of gated channel will respond to voltage across the membrane

stimulus

depolarization/hyper polarization

in a graded potential, the amplitude of the ______________ is proportional to the _________________

calcium

influx of which ion through a voltage gated channel is triggered by an AP traveling across the membrane of a cardiac cell into a T tubule

sarcoplasmic reticulum

when Ca2+ enters the cytoplasm of the cardiac cell, additional calcium is released from the...

sparks (size determined by the amount of Ca2+)

signals (sum of sparks)

release of calcium from the SR results in the formation of calcium _________ which turn into calcium __________

troponin (initiates movement of tropomyosin and allows actin and myosin to interact resulting in contraction)

calcium signals lead to calcium ions binding to...

when calcium unbinds from troponin

when does relaxation of the sarcomere begin

it is pumped back into the SR and pumped into the ECF (NCX pump)

how is calcium removed from the cytoplasm of the cardiac cell following unbinding from troponin

the NCX pump (2 calcium out, 3 sodium in) and the sodium potassium pump (3 sodiums out and 2 potassiums in)

which 2 pumps work to restore resting membrane potential

sodium potassium pump

how is the Na+ gradient maintained within cardiac cells

active cross bridges between actin and myosin

the force of contraction in a cardiac muscle cell is proportional the the number of...

starting length of the sarcomere, the longer the stronger

what other factor besides crossing over of actin and myosin plays a role in the strength of myocardial contraction contraction?

contractile cells and auto rhythmic

what are the types of myocardial cells in the heart

myocardial cells have a longer AP due to calcium entering the cell in addition to Na+

what is the difference between APs in skeletal muscle cells and myocardial contractile cells

they are generated spontaneously due to an unstable resting membrane potential

what are characteristics of APs generated by auto rhythmic cells

-90mV

what is the resting membrane potential in a cardiac cell

opening of sodium channels in the cell membrane via gap junctions

what causes rapid depolarization of cardiac muscle cells

close

open

sodium channels ___________ when the cell membrane reaches maximum depolarization, potassium channels ________ leading to initial repolarization (1)

calcium channels open, fast potassium channels close (maintains depolarization)

what is occurring in number 2 of the cardiac muscle AP