Studied by 2 peopleThe refractory period occurs when_______.
voltage-gated sodium channels are inactivated and potassium channels are open
A threshold stimulus immediately __________
opens voltage-gated sodium channels
In myelinated axons, an action potential occurs _________ and they propagate __________.
at nodes of Ranvier; rapidly
Concentration gradients exist across the plasma membrane., Specifically, there are ___________.
more potassium ions inside and more sodium ions outside of the plasma membrane
The value of the resting membrane potential is ___________.
-70 mV
The Na+/K+ pump transports ________.
Na+ out of and K+ into the cell
Neurons that lie entirely within the CNS are called ___________.
interneurons
Which of the following glial cells become part of the blood-brain barrier?
astrocytes
A neuron under the influence of a neurotransmitter that opens K+ channels will _____________ (two answers)
be less likely to fire an action potential
become hyperpolarized
Ouabain, a specific inhibitor of the Na+-K+ pump, is applied to a neuron. What effect will this have on the subsequent action potential fired by that neuron?
There will be no effect
During the repolarization of a neuron:
K+ moves from cell to ECF
Release of a neurotransmitter requires: (two answers)
Ca2+ entry into the cell
an action potential
Communication between neurons is not always one-to-one. When a group of presynaptic neurons provides input to a smaller number of post-synaptic neurons it is called:
convergence
What is the function of the cerebrospinal fluid? (three answers)
the CSF provides a route by which wastes can be removed from the CNS
the CSF provides protective padding for the brain
the buoyancy of the CSF reduces the weight of the brain
The purpose of the blood-brain barrier is to
protect neurons from potentially harmful substances in the blood
The pyramids are a region within the medulla responsible for which of the following?
The fact that each side of the brain controls the opposite side of the body
What causes the depolarization phase of the action potential?
K+ exiting the cell through voltage-gated ion channels
During the rising phase of the action potential ______________.
sodium moves down both a concentration and electrical gradient.
Which of the following is TRUE about one of the two gates in NA+ channels in axons?
The closing of the inactivation gate stops the depolarizing during an action potential
If a neuron has receptors for a particular neurotransmitter it will
respond in a similar way to an agonist of that neurotransmitter
The ability of the nervous system to change activity at the synapse is called
synaptic plasticity
Neural tissue has a minimal extracellular matrix so support and protection come from external sources. Which of the following are involved in this support and protection? (four answers)
cerebrospinal fluid
the meninges
glial cells
outer casing of bone
Each of the following has lower concentrations in CSF compared with plasma EXCEPT:
a. Ca2+
b. Na+
c. K+
d. HCO3-
e. glucose;
Na+
Each of the following regarding the blood-brain barrier is true except:
gap junctions exist between endothelial cells of the capillaries → has tight junctions
Except in periods of starvation, the only fuel for the brain are __________ so 15% of blood pumped by the heart goes to the brain to supply enough __________ from which to generate ATP.
glucose - oxygen
Which of the following pairings is not correct?
Thalamus; relays and modifies information going to and from the cerebellum → thalamus responsible for relaying information from the senses to the cerebral cortex
Midbrain:
Relays signals & visual reflexes
Medulla Oblongata:
Contains control centers for BP & breathing
Hypothalmus:
hemostatsis
Cerebellum:
Mvmt & cordination
If you close your eyes and reach forward with one hand you will know the position of that hand because of ___________ activation.
proprioceptor
A two-point discrimination test allows for the differentiation between
receptive fields
Which of the following receptors fire rapidly when first activated, then slow and maintain their firing as long as the stimulus is present?
tonic receptors
The intensity of a sensory stimulus is coded by
the frequency of action potentials
A blow to the eye causes us to see a flash of light or "stars" even though the photoreceptor is not being activated by light. This can be explained by which of the following?
labeled line coding
Chemicals such as histamine, prostaglandins, serotonin, and substance P
only sensitive and activate nociceptors
Which of the following physiological responses results from sympathetic action? (three answers)
increase heart rate
dilation of blood vessels
stimulation of glycogenolysis
The neurotransmitter norepinephrine is synthesized from
tyrosine
The receptor found on most parasympathetic target cells is
muscarinic cholinergic
The enzyme monoamine oxidase (MAO) breaks down
catecholamines
The synapse of a somatic motor neuron on a muscle fiber is called the
neuromuscular junction
When a skeletal muscle lengthens, its sarcomeres
lengthen
Which of the following characteristics differentiates skeletal muscle from both cardiac and smooth muscle? (two answers)
multinucleated fibers
movement is controlled by a somatic motor neuron
Why does rigor mortis occur after death?
myosin is tightly bound to actin
If you want to study smooth muscle, it doesn't matter what organ it comes from because all smooth muscle is alike.
False
Which of the following phases of a muscle twitch requires ATP? (two answers)
contraction period
relaxation period
In smooth muscle, the Ca2+ for contraction comes from: (two answers)
extracellular fluid
sarcoplasmic reticulum
Drug "X" inhibits acetylcholinesterase action within the neuromuscular junction. What would drug "X" do to the membrane potential of the muscle fiber?
it would remain depolarized
Which of the following is NOT true regarding the innervation of skeletal muscle?
multiple motor units innervating a skeletal muscle also contact all at once
The function of transverse tubules is to
rapidly conduct action potentials to the interior of the muscle fiber
Each myosin head has a binding site for
actin and ATP
The somatic motor neurons that innervate skeletal muscle fibers are called
alpha motor neurons
Spinal reflexes are to the spinal cord as cranial reflexes are to the
brain
Stretching the muscle spindle causes
reflex contraction of the muscle
Which of the following helps us to maintain body position as we move through space?
postural reflexes
Convergence describes
how multiple primary sensory neurons synapse on a single secondary neuron.
Visceral pain is poorly localized and can be perceived to originate from a region of the body that is different from its actual location; this is called
referred pain
Chronic pain is
only pathological
The gate control theory of pain modulation states that pain transmission can be blocked by:
mechanical stimulation of A-beta fibers
The vitreous chamber of the eye
helps to stabilize the structure of the eye and the retina
The presence of two peripheral efferent neurons in a pathway is typical of the __________ division
autonomic
The motor end plate is
a folded area of muscle cell membrane with ACh receptors clustered at the top of each fold
For antagonist's muscle groups to move a limb, flexor contraction occurs coincident with:
relaxation of the extensor
The contraction cycle is triggered by the rise in __________ released from the sarcoplasmic reticulum
Ca2+
A motor unit consists of
one neuron and all the skeletal muscle fibers it controls
Compared to skeletal muscle, the contraction of smooth muscle cells is
sustained without fatigue
Which of the following statements is true? (ALL ARE TRUE)
cranial reflexes are integrated into the brain
visceral reflexes are controlled by autonomic neurons
reflex movements are integrated primarily into the spinal cord
spinal reflexes do not require input from the brain
The _________ supply blood to the heart muscle itself
coronary arteries
The right ventricle pumps ________ blood into the ___________ circulation
deoxygenated; pulmonary
Which of the following is INCORRECT regarding diastole (filling of the heart)?
pressure in the ventricles is greater than in the atria
Which of the following are common mechanisms used to control blood flow to different areas of the body? (two answers)
vasoconstriction of the blood vessels
vasodilation of blood vessels
During the T wave, which of the following is true?
both ventricles are repolarizing
Plasma proteins decrease in a person with liver failure. What effect does this have on capillary filtration/absorption?
net filtration increases
The term for the production of blood cells is
hematopoiesis
The glycoprotein thrombopoietin (TPO) regulated the growth and maturation of
megakaryocytes
Calculate mean arterial pressure if a person has a blood pressure reading of 107/72
84 mm Hg
(T/F) Sympathetic output from the cardiovascular control center acting on b2-adrenergic receptors causes vasodilation in the heart and vasoconstriction in skeletal muscles
False
Which of these statements about the heart is false?
the action potential of a cardiac contractile cell is identical to that of a skeletal muscle cell
Which of the following is the SAME regarding the action potential of a neuron and of a myocardial contractile cell? (two answers)
Na+ influx is responsible for the depolarization phase
K+ efflux is responsible for the rapid depolarization phase
A withdrawal of parasympathetic nerve activity has which of the following effects?
increases heart rate
Blood flow through an arteriole _______ when it dilates
increases
If one arteriole constricts and nothing else changes, what will happen to mean arterial pressure?
it increases
Systemic arterioles ___________ in response to decreasing oxygen
dilate
Blood flow velocity is slowest in the
capillaries
Which of the following vessels undergo a change in diameter based on neural input? (two answers)
arterioles
veins
If blood pressure increases, the
net filtration across the capillary walls increases
Which of the following is/are correct for arteries but not veins?
store pressure generated by the heart
Local control of arteriolar resistance leads to an increase in blood flow to tissue when
H+ level increases
Which of the following is NOT a mechanism used by the lymphatic system to control the flow of lymph?
osmosis
Which blood elements are lacking a nucleus? (two answers)
erythrocytes
platelets
Which of the following is the major contributor to the fact that water gets pulled from the interstitial fluid into capillaries?
albumins
Normally, whole blood is composed of _____________% cells and ____________% plasma
40; 60
Which of the following does not promote platelet activation and/or aggregation?
prostacyclin
The end product of the coagulation cascade is
cross-linked fibrin
Antibiotic drugs act against
bacteria
The body's specific immune response is mediated by
antibodies
Which of the following chemicals stimulate pain receptors?
bradykinins
During a primary immune response; which antibody level is increased?
IgM
IgG
Secondary Immune Response Can cross placenta Responsible for resistance against viruses, bacteria, & bacterial toxins
IgA
External (grandular) Secretions
Note
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