Midterm 1 Review Content Flashcards
What does physiology study
the NORMAL functioning of the human body
What are the main themes in physiology
structure/function
energy
information flow
homeostasis
List the organization levels of the body from smallest to largest
chemical, cellular, tissue, organ, system, organism
What type of science is physiology
integrative
- most research focuses on the molecular and cellular levels
What are the 4 types of tissues and what are each of their basic functions
muscle
- voluntary and involuntary movement as well as strength and structure
connective
- holds parts of the body together and has an extensive ECM
epithelial
- protection of the internal environment, regulates the exchange of materials
neural
- carry information and signals from one part of body to the next (very LITTLE ECM)
What is the function of muscle tissue?
voluntary movement and structure
What is the function of neural tissue
carry signals
What is the function of the connective tissue
structure
What is the function of epithelial tissue
inner protection
What tissue type has the most extensive ECM
connective
What tissue type has the least ECM
neural
What are the 5 types of epithelial tissue
exchange
ciliated
transporting
secretory
protective
What type of tissue is the skin?
epithelial; more specifically protective
What type of tissue lines the inner female reproductive system (think similar to the tissue that lines airways)
epithelial; more specifically ciliated
What are the 5 types of connective tissue
loose
dense
adipose
blood
supporting
What is another term for adipose tissue
fat
What is the least dense type of connective tissue
blood
What is the most dense type of connective tissue
supporting (cartilage and bones)
What are the three types of muscle tissue
skeletal, smooth, and cardiac
What is the function of skeletal muscle
voluntary movement
What is the function of smooth muscle
involuntary movement
- essential for moving substances in/out of the body
What is the function of cardiac muscle
blood flow
What are the two types of neural cells
neurons and glial cells
What are neurons
neural muscle cells that relay signals
What are glial cells
neural muscle cells that support the neurons
What are the 10 major organ systems and what are each of their functions
circulatory; bloodflow
respiratory; breathing
digestive; digestion
endocrine; homeostasis
excretory; urination
nervous; cell signalling
reproductive; reproduction
musculoskeletal; movement
integumentary; outer layer (skin)
immune system; disease prevention
What is the “why” in physiology
function
What is the “how” in physiology
mechanism
What is the result of homeostatic control
oscillation around a set point in the body
What does the term acclimatization mean?
environmentally induced change and adaptation of the body’s function without genetic change
What are the 4 main types of cell-cell communication
gap junctions
contact dependant
short distance
long distance
What are gap junctions
protein channels called CONNEXONS allow communication between adjacent cells - these connexons can open and close as needed (controlled flow)
What is contact dependant signalling
the interaction between membrane connectivity between two cells (self explanatory)
What is local communication
occurs via both paracrine AND autocrine signals
What are autocrine signals
chemicals released that act on the same cell that produced them
What are paracrine signals
chemicals released that act on neighbouring cells (immediate vicinity)
What is long-distance communication
chemical/electrical signalling is used to relay signals across long distances in the body
Why do some cells respond to a given signal while others know not to respond
cells have specific receptor proteins that allow for signals to be relayed
- if they do not have matching receptors, the signal is not relayed
What type of protein are protein receptors
transmembrane proteins (glycoproteins)
Where can receptor proteins be found
MOSTLY plasma membrane, but also in the nucleus and cytoplasm
What is the 4-step process for a receptor to relay a signal
- signalling molecule (neurotransmitter) binds to receptor
- activated receptor interacts with molecules inside the cell to start a signal
- signal is carried to the appropriate spot; signal transduction
- response occurs
What happens when a signal has reached its target
signal transduction: a response is produced
What is the reaction between one or more organs controlled from somewhere else in the body referred to
reflex control
*this was a sample quiz question
What type of communication completed reflex signalling
long-distance communication
What creates stability
the balance between input and output
Can set points be reset?
yes
Explain a negative feedback loop
a change that opposes or removes a signal to return a cell to its original state
(ie. blood pressure)
Explain a positive feedback loop
response sends a signal, which in turn increases the response, and this cycle continues until an external signal shuts off the cycle
(ie. labour)
What is feedforward control
when a change is predicted to happen, and the response is kickstarted by anticipation (to prevent change)
(ie. thought of food)
What is circadian rhythm
the natural cycle of physical, mental, and behavioural changes throughout a 24-hour cycle
What are the 3 MAIN reasons for having a nervous system
receive, integrate, and transduce signals
What is the order by which an external signal is received and carried
stimulus, sensor, afferent pathway, integrating center, efferent pathway, target, response
*this is important for understanding neurons
What are the two main parts of the nervous system
CNS and PNS
What are the two sub branching parts of the CNS
brain and spinal cord
What are the two sub branching parts of the PNS
somatic and autonomic
What are the two sub-branches of the autonomic pathway
sympathetic and parasympathetic
What are the two types of PNS neurons
sensory (afferent) and motor (efferent)
What is a synapse
the gap between two linking neurons where a chemical signal is transported from one neuron to the next
What are the 5 types of neurons when thinking STRUCTURALLY
pseudounipolar
bipolar
anaxonic
multipolar-CNS
multipolar-efferent
What are pseudounipolar neurons
axons and dendrites fuse (so they are all connected, unlike most other neurons)
What are bipolar neurons
contain one axon and one dendrite (think bi-polar, ‘bi’ meaning 2; one on each end)
What are anaxonic neurons
have no true axons, therefore they do not produce an action potential, only regulate electrical changes in adjacent neurons
What are multipolar-CNS neurons
most common in CNS - have many dendrites but no long extension of the axon (tons of branches on either end, but no long extension like other neurons)
What are multipolar-efferent neurons
the “stereotypical” neuron
- has branching dendrites and a long axon, with axon terminals at the end
What type of neurons are pseudounipolar and bipolar neurons
sensory (afferent) neurons
What type of neurons are anaxonic and multipolar-CNS neurons
interneurons
What type of neurons are multipolar-efferent neurons
motor (efferent) neurons (self explanatory)
What are the 3 FUNCTIONAL categories of neuron
sensory (afferent), inter, and motor (efferent)
Which type of neuron receives a signal and transports it TO the CNS (think directionally how each term makes sense)
afferent (sensory) neurons
Which type of neuron transmits info WITHIN the CNS (think directionally how each term makes sense)
interneurons
Which type of neuron takes info FROM the CNS (think directionally how each term makes sense)
efferent (motor) neurons
Which type of neuron is most abundant in the body
interneurons (96% of neurons)
What type of cell communication do GLIAL cells use
local communication (cannot carry signals over long distances but can communicate with nearby cells)
In what two ways do glial cells assist neurons
- aid in nerve impulse conduction
- maintain the microenvironment around neurons
What are the two types of PNS glial cells and what are they used for
Schwann cells (special cells wrapped around axons); create myelin, which acts as an electrical insulator
Satellite cells (non-myelinating Schwann cells); support the nerve cell bodies (soma)
What are the 4 types of glial cell found in the CNS and what are they used for
oligodendrocytes; CNS version of Schwann cells
astrocytes; kind of like satellite cells from PNS, but also connect the neurons to blood vessels
microglia; macrophage-like immune cells that remove damaged cells and forge in invaders
ependymal cells; produce cerebral spinal fluid (creates selectively permeable sections of the brain)
What are oligodendrocytes
CNS version of Schwann cells
What are astrocytes
connect blood vessels to neurons (and maintain environment)
What are microglia cells
specialized immune cells (like macrophages) that remove damaged or forge in invaders
What are ependymal cells
create selective permeability in the brain and produce cerebral spinal fluid
Do all living cells have membrane potential?
yes!
What ion is concentrated INSIDE the cell, and what is the inner-cell’s charge
K+ (the inner charge is -ve)
What ion(s) is(are) concentrated OUTSIDE the cell, and what is the outer-cell’s charge
Na+, Cl-, and Ca2+ (the outer charge is +ve)
Are anions or cations more concentrated in the ICF
anions (negatively charged)
Because of their charge, _________ do not move across the membrane
anions
Which can move more easily across the membrane; Na+ or K+?
K+ : there are more voltage-gated K+ channels so it can move more easily than Na+
What does (Eion) mean in terms of membrane potential
equilibrium potential of the cell: the membrane potential that EXACTLY opposes the concentration gradient of the cell
At equillibrium potential, ___________ & __________ forces act opposingly
chemical and electrical
In relation to calculating the electrical potential needed to find equilibrium state, what is the specific condition that must be followed
can only be done for an INDIVIDUAL ion (must do multiple calculations for whatever varying ions are present)
What is the electrical potential for K+
-90mV
What is the electrical potential for Na+
+60mV
The Nernst equation looks at the equilibrium potential if the membrane were permeable to only ____ ion
one
What is typical resting potential
-70mv
What does the GHK equation predict
the membrane permeability of MULTIPLE ions
What is the difference between the Nernst equation and the GHK equation
Nernst; only one ion considered
GHK; multiple ions considered
How is resting membrane potential calculated
(concentration gradient x membrane permeability) of each ion added
What is depolarization
a decrease in membrane potential difference (becomes less negative)
What is hyperpolarization
an increase in membrane potential difference (becomes more negative)
What are graded potentials
triggered by the opening/closing of channels, which are started when ions enter the cell from the ECF, but only travel short distances
Why are they called “graded” potentials
because the strength of the triggering event is proportional to the amplitude of the potential
Where do graded potentials occur
dendrites or soma
Why do graded potentials lose strength quickly
- leaky channels
- cytoplasmic resistance
What is the strength of a signal determined by?
the number of ions transported into the cell
What causes ions to enter the cell?
neurotransmitters bind to receptors on the cell membrane, which opens channels
What type of signal is used for short distance
graded potentials
What type of signal is used for long term distance
action potentials
How do action potentials differ from graded potentials
- action potentials do not vary in strength/amplitude
- action potentials don’t diminish in strength (graded potentials do)
Where are action potentials initiated
the trigger zone
What is the MINIMUM depolarization necessary for action potential called
threshold potential
What happens if depolarization does not reach the threshold?
action potential is not initiated
What (other than threshold potential) can initiate action potentials
graded potentials
How do graded potentials initiate action potentials
they gather at the trigger zone until the sum of the potentials reaches threshold, which is when action potential is initiated
What are depolarizing graded potentials
called “excitatory post synaptic potentials” (EPSP’s); makes membrane potential LESS negative, which brings membrane potential closer to threshold potential
** brings axon closer to firing
What are hyper polarizing graded potentials
called “inhibitory post synaptic potentials” (IPSP’s); makes membrane potential MORE negative, which pushes membrane potential further from threshold potential
** takes axon further from firing
What are the steps of action potential?
*think back to review graph shown in lecture
- resting potential
- depolarizing stimulus (less negative)
- membrane depolarizes to the threshold (Na+ and K+ channels begin to open)
- rising phase (Na+ causes cell to depolarize)
- Na+ channels close and K+ channels open
- repolarizing phase (K+ begins to exit)
- hyperpolarization phase (overshoots resting potential because K+ channels still open)
- K+ channels close
- membrane returns to resting state
What are the 2 gates on an Na+ voltage-gated channel
activation and inactivation (self explanatory)
Does it take few or many action potentials to have ions cross the gradient
MANY
What is the refractory period in hyperpolarization
absolute refractory; no action potentials at all can be stimulated
relative refractory; a LARGE stimulus is required to bring forth action potential
Why can’t action potential occur during absolute refractory
membrane must repolarize for Na+ channel to return to normal state
Why does it take such a large stimulus during relative refractory for action potential to occur
K+ channels are still open, so more Na+ is needed to repolarize
Why is the refractory period important
sets the direction of current flow and prevents action potential from flowing backwards
Why can’t action potentials move backwards
when travelling down the axon, the previous area had just undergone depolarization, therefore is in the refractory period (cannot have action potential in the refractory)
Why can action potential move long distance
when depolarizing down the axon, the neighbouring area ahead is depolarized with it, creating a chain reaction down the axon
What two factors determine the speed at which action potential travels
- diameter of the axon (greater diameter = greater conduction)
- resistance of axon membrane ion leakage out of the cell (insulating the cell reduces ion leakage; speeds conduction)
What are nodes of ranvier
the unmyelinated spaces in between insulated parts on the axon
What is saltatory conduction
when action potentials jump from one node of ranvier to the next (faster conduction)
What are the 3 components of a synapse
presynaptic cell
synaptic cleft
post-synaptic cell
which type of synapse makes up the vast majority of synapses
chemical synapses
What are the two types of synapse
electrical and chemical
What are the 2 main types of neurotransmitter
acetylcholine and amines
What are neurons that secret ACh called
cholinergic
What are the two types of cholinergic receptors
nicotinic
muscarinic
What are nicotinic receptors
receptor-operated channels
What are muscarinic receptors
coupled G-protein receptors
What neurotransmitters fall in the amine category
epinephrine, dopamine, and norepinephrine
Neurons that secret norepinephrine are called ___________
adrenergic
What are the two types of adrenergic receptors (though both are G-protein coupled)
alpha and beta
What are catecholamines
amino acid tyrosine is converted into things such as dopamine, epinephrine, and norepinephrine (neurotransmitters)
What happens to neurotransmitters that are not used
they diffuse back into the axon terminals of the presynaptic neuron
Which type of neurotransmission is discussed in this course
PNS; more specifically the efferent branch
The efferent branch of the PNS is divided into two parts; the __________ and the ____________
autonomic and somatic divisions
What type of muscle tissue involves the somatic branch
skeletal
What type of muscle tissue involves the autonomic branch
smooth and cardiac
What are the two branches of the autonomic system
sympathetic and parasympathetic
What is the sympathetic system involved in
“fight or flight”
- exercise, stress, etc.
What are the general neuron structures in the autonomic system
two-neuron chain, separated by a synapse called the autonomic ganglia (preganglionic and postganglionic)
What are the 2 primary transmitter of the autonomic system
ACh and norepinephrine
What neurotransmitter is released by ALL preganglionic neurons
ACh (and by most postganglionic too)
What is released by postganglionic sympathetic neurons
norepinephrine
How do autonomic synapses differ from model synapses
autonomic axons end with swollen areas called varicosity (think varicose veins)
** this was a sample quiz question
What are the targets of the autonomic pathway
innervates and synapse structure
What are the two types of receptor
adrenergic and cholinergic
What do adrenergic receptors respond best to
epinephrine and norepinephrine
What do cholinergic receptors respond best to
ACh, nicotine and muscarine
Adrenergic receptors act via __-_________
G-proteins
a-receptors cause….
increase in Ca2+ in cytoplasm
b-receptors cause….
increase in cAMP production
Which type of receptor acts on skeletal muscle
nicotinic (cholinergic)
What are the two parts of the adrenal gland
adrenal cortex and adrenal medulla
- adrenal medulla; modified sympathetic ganglion
What are the special cells called that secrete epinephrine
Chromaffin cells
In the somatic division, if a signal is relayed to skeletal muscle tissue, what is the ONLY possible occurrence
muscle stimulation (cannot facilitate muscle relaxation)
** this is a practice quiz question
What is a neuromuscular junction
the synapse between skeletal muscle and a somatic neuron
What is the synapse between a somatic neuron and skeletal muscle called
a neuromuscular junction
In a neuromuscular junction, there is a sheath of _______ _______ at the axon terminals
Schwann cells
What are the 3 components of the neuromuscular junction
presynaptic axon terminal
synaptic cleft
postsynaptic axon membrane of skeletal fiber (modified into a motor end plate containing nicotinic receptors)
What is temporal summation
when a repeated stimulus of the same intensity is applied to the same region, causing an increase in pain experienced
