Week 5 Quiz Questions

Question 1

The neurotransmitter at the preganglionic synapse is ____________, which binds to ___________ receptors, while the sympathetic postganglion synapse features the neurotransmitter ____________ and the parasympathetic features the neurotransmitter ____________, which binds __________ receptors.

Answer 1

The neurotransmitter at the preganglionic synapse is ACETYLCHOLINE, which binds to nAChRs/NICOTINIC ACETYLCHOLINE receptors, while the sympathetic postganglion synapse features the neurotransmitter EPINEPHRINE/NOREPINEPHRINE and the parasympathetic features the neurotransmitter ACETYLCHOLINE, which binds mAChRs/MUSCARINIC ACETYLCHOLINE receptors

Question 2

An exception to a two-neuron chain in the sympathetic nervous system is the _______ which is directly innervated and in a sense is really an expanded ganglia, meaning the neurotransmitter __________ is released onto it.

Answer 2

An exception to a two-neuron chain in the sympathetic nervous system is the ADRENAL MEDULLA which is directly innervated and in a sense is really an expanded ganglia, meaning the neurotransmitter ACETYLCHOLINE is released onto it. ***Adrenal medulla is the center part of the adrenal gland and gets direct innervation from the sympathetic preganglionic axon from the spinal cord.

Question 3

What Gα subunit corresponds to adrenergic receptor α1?

Answer 3

Gαq –> Ip3 binds to Ip3R, Calcium is released from SR and muscle contracts

Question 4

What Gα subunit corresponds to adrenergic receptor α2?

Answer 4

Gαi

Question 5

What Gα subunit corresponds to adrenergic receptor β1?

Answer 5

Gαs

Question 6

What Gα subunit corresponds to adrenergic receptor β1?

Answer 6

Gαs

Question 7

What Gα subunit corresponds to adrenergic receptor β3?

Answer 7

Gαs

Question 8

There are five types of muscarinic receptors m1-m5. The two principle receptors in the parasympathetic nervous system are ____ in the heart and ____ in smooth muscle, glands and endothelial cells

Answer 8

There are five types of muscarinic receptors m1-m5. The two principle receptors in the parasympathetic nervous system are M2 in the heart and M3 in smooth muscle, glands and endothelial cells

Question 9

In order to stimulate dopaminergic signaling people with Parkinson’s disease are often prescribed L-dopa, a precursor of dopamine, which can pass the blood brain barrier, unlike its precursor tyrosine. L-dopa is metabolized into dopamine, which itself can be converted into:

Answer 9

Norepinehprine

**Tyrosine —-(Tyrosine Hydroxylase)—> Catecholamines L-Dopa –> Dopamine –> Epinephrine –> Norepinephrine

Question 10

Muscarinic AChR are _______________ receptors, while nicotinic AChR are ____________ receptors

Answer 10

Muscarinic AChR are GPCRs, while nicotinic AChR are ligand-gated ion channel receptors

Question 11

What are the two type of cholinergic receptors?

Answer 11

Nicotinic AChRs (nAChRs) = receptor ion channel complexes Muscarinic AChRs (mAChRs) = GPCR

Question 12

The M2 receptor in the heart influences cardiac cycle because:

Answer 12

G -beta,gamma stimulates a K= channel

Question 13

Baroreceptors are:

Answer 13

Mechanoreceptors

**located in carotid sinus, scattered through aortic arch

Question 14

Which branch of the ANS is the adrenal medulla innervated by?

Answer 14

ACh is released from the Autonomic preganglionic neuron onto adrenal medulla cells that contain nictonicic AChRs. There is no second neuron in this pathway, so there are no adrenergic receptors in the adrenal medulla.

Question 15

What makes innervation of the Adrenal gland so special?

Answer 15

Sympathetic preganglionic fiber directly innervates adrenal medulla.

***There is NO post-synaptic neuron, rather the cells release Norepi/epi into blood directly, thus the two act as HORMONES rather than neurotransmitters as they do elsewhere in the sympathetic NS.

Question 16

What are the two primary catabolism systems for catecholamines?

Answer 16

In sympathetic nerves, MAO (monamine oxidase) is the only metabolizing enzyme. The metabolites produced by MAO can be further metabolized by COMT.

Question 17

In the presence of high levels of Norepinephrine and Epinephrine, what will be found in large amounts in the urine?

Answer 17

Vanillyl mandelic acid (VMA)

Question 18

You are treating a patient with a pheochromocytoma (a tumor of the adrenal gland) that is causing here to experience a menagerie of sympathetic ANS symptoms. Explain why she felt hot but her hands and feet felt cold.

Answer 18

The α1 receptor activate Gq, leading to an increase of Ca and consequential smooth muscle contraction. Cutaneous blood vessels constrict and blood is shunted from extremities to core.

Question 19

You are treating a patient with a pheochromocytoma (a tumor of the adrenal gland) that is causing here to experience a menagerie of sympathetic ANS symptoms. Explain why her heart rate is super duper fast.

Answer 19

Binding of β1 receptor causes increase in cAMP and PKA activity and consequential contraction of cardiac muscle.

Question 20

You are treating a patient with a pheochromocytoma (a tumor of the adrenal gland) that is causing here to experience a menagerie of sympathetic ANS symptoms. Explain why she is experiencing visual disturbance.

Answer 20

Binding of the β2 receptor with Gs subunit, leading to increased level of cAMP and PKA with consequential dilation in the ciliary body, including muscles of the Iris, resulting in visual disturbance.

Question 21

A new patient comes into your clinic, and after a careful examination, you decide to prescribe a medication that mimics acetylcholine released from postganglionic ANS neurons acting on cholinergic receptors. Based on this medication choice, what symptoms from the list below was the patient most likely experiencing?

a. Constricted pupils; her pupils cannot dilate
b. Decreased heart rate (bradycardia)
c. Orthostatic hypotension
d. Syncope
e. Dry mouth and eyes; glandular fluids need to be increased

Answer 21

Dry mouth and eyes; glandular fluids need to be increased

If the PANS was not functional, there would be decreased salivation and lacrimation. In cases A-D, if you prescribe this medication you would cause further problems: more constriction, the heart rate would decrease more (probably cause death), and the person would be more likely to have problems with hypotension and syncope.

Question 22

What is a useful acronym to describe the effects of Cholinergic Agonists?

Answer 22

SLUDGE!!

Salvation Lacrimation Urination Defecation Gastric Motility Emesis

Question 23

What is the function of the sarcoplasmic reticulum in skeletal muscle?

Answer 23

Cellular storage of Calcium.

Question 24

Gap junctions allow the signal to contact and spread in a wave from one cardiac muscle cell to another, synchronizing contraction. Gap junctions are located in which subcellular structures?

Answer 24

Intercalated discs

Question 26

Mr Green is a 60-year-old man with poorly controlled hypertension of 170/110 mm Hg. He is to receive minoxidil. Minoxidil is a powerful arteriolar vasodilator that does not act on autonomic receptors. Which of the following effects will be observed if no other drugs are used?

(A) Tachycardia and increased cardiac contractility

(B) Tachycardia and decreased cardiac output

(C) Decreased mean arterial pressure and decreased cardiac contractility

(D) Decreased mean arterial pressure and increased salt and water excretion by the kidney

(E) No change in mean arterial pressure and decreased cardiac contractility

Answer 26

Because of the compensatory responses, a drug that directly decreases blood pressure through a decrease in peripheral vascular resistance will cause a reflex increase in sympathetic outflow, an increase in renin release, and a decrease in parasympathetic outflow. As a result, heart rate and cardiac force will increase. In addition, salt and water retention will occur. The answer is A.

Question 27

A 3-year-old child has been admitted to the emergency department having swallowed the contents of 2 bottles of a nasal decongestant. The active ingredient of the medication is a potent, selective α-adrenoceptor agonist drug. Which of the following is a sign of α-receptor activation that may occur in this patient?

(A) Bronchodilation

(B) Cardiac acceleration (tachycardia)

(C) Pupillary dilation (mydriasis)

(D) Renin release from the kidneys

(E) Vasodilation of the blood vessels of the skin

Answer 27

Mydriasis can be caused by contraction of the radial fibers of the iris; these smooth muscle cells have α receptors. All the other listed responses are mediated by β adrenoceptors (Table 6–4). The answer is C.

Question 28

Full activation of the parasympathetic nervous system is likely to produce which of the following effects?

(A) Bronchodilation

(B) Decreased intestinal motility

(C) Increased thermoregulatory sweating

(D) Increased pupillary constrictor tone (miosis)

(E) Increased heart rate (tachycardia)

Answer 28

Parasympathetic discharge causes bronchial and intestinal smooth muscle contraction and bradycardia. Thermoregulatory (eccrine) sweat glands are innervated by sympathetic cholinergic fibers, not parasympathetic. The answer is D.

Question 29

The postganglionic neuron releases a signal on an effector responsible for pupillary constrictor smooth muscle cell, what receptor type does the signal bind?

(A) Alpha1 adrenoceptor

(B) Beta2 adrenoceptor

(C) M3 cholinoceptor

(D) Ng cholinoceptor

Answer 29

The nerves innervating the pupillary constrictor muscle are postganglionic parasympathetic cholinergic nerves. The pupillary dilator muscle contains α1adrenoceptors. The answer is C.

Question 30

Nicotinic receptor sites do not include which one of the following sites?

(A) Bronchial smooth muscle

(B) Adrenal medullary cells

(C) Parasympathetic ganglia

(D) Skeletal muscle end plates

(E) Sympathetic ganglia

Answer 30

Both types of ganglia and the skeletal muscle neuromuscular junction have nicotinic cholinoceptors, as does the adrenal medulla (a modified form of sympathetic ganglionic neuron tissue). Bronchial smooth muscle contains muscarinic cholinoceptors and noncholinergic receptors. The answer is A.

Question 31

Several children at a summer camp were hospitalized with symptoms thought to be due to ingestion of food containing botulinum toxin. Which one of the following signs or symptoms is consistent with the diagnosis of botulinum poisoning?

(A) Bronchospasm

(B) Cycloplegia

(C) Diarrhea

(D) Skeletal muscle spasms

(E) Hyperventilation

Answer 31

Botulinum toxin impairs all types of cholinergic transmission, including transmission at ganglionic synapses and somatic motor nerve endings. Botulinum toxin prevents discharge of vesicular transmitter content from cholinergic nerve endings. All of the signs listed except cycloplegia indicate increased muscle contraction; cycloplegia (paralysis of accommodation) results in blurred near vision. The answer is B.

Question 32

Which one of the following is the primary neurotransmitter agent normally released in the sinoatrial node of the heart in response to a blood pressure increase?

(A) Acetylcholine

(B) Dopamine

(C) Epinephrine

(D) Glutamate

(E) Norepinephrine

Answer 32

When blood pressure increases, the parasympathetic system is activated and heart rate decreases. Acetylcholine is the transmitter at parasympathetic nerve endings innervating the sinus node (nerve endings of the vagus nerve). The answer is A.

Question 33

Reuptake carrier NET transports norepinephrine back into the nerve ending after release. It can be blocked by what drug?

Answer 33

Cocaine!

Question 34

What is the function of the sarcoplasmic reticulum in skeletal muscle?

Answer 34

Cellular storage of Ca2+

Question 35

Gap junctions allow the signal to contact and spread in a wave from one cardiac muscle cell to another, synchronizing contraction. Gap junctions are located in which of the following subcellular structures?

Answer 35

Intercalated discs

Question 36

What causes an end-plate potential?

1) Ryanondine receptors
2) Voltage-gated sodium ion channel opening
3) L-type calcium channels
4) All of these
5) Acetylcholine receptor opening

Answer 36

Acetylcholine receptor opening

Question 37

True or false: Calcium binds to the regulatory protein, tropomyosin, to begin crossbridge formation.

Answer 37

Calcium binds to the protein, troponin, not tropomyosin. Once troponin is bound by calcium, the tropomyosin moves away from the binding site so that actin and myosin can interact to create a crossbridge.

Question 38

Smooth muscle contraction requires which two proteins not involved in striated muscle contraction?

Answer 38

Calmodulin / myosin light chain kinase

There is no tropomyosin in smooth muscles; they rely on calmodulin signaling.

Question 39

Slow type I muscle fibers contain more of which cellular organelle so they can produce energy through aerobic mechanisms as compared to type II fibers?

Answer 39

mitochondria

Question 40

What is the high energy molecule that can be used to generate ATP in skeletal muscles during the first 15s of an activity?

Answer 40

creatine phosphate

phosphocreatine

creatine kinase

Question 41

Which of the following best describes a muscle when the tension remains almost constant while the muscle changes in its length?

Answer 41

Isotonic contraction

All contractions begin just as tension developing on the muscle; initially tension increases, but length stays the same. In isotonic contractions the tension remains constant, which means that the tension exceeds the load. In a lengthening contraction, the load exceeds the tension.

Question 42

The amount of tension generated by a skeletal muscle:

1) all of these are true
2) is increased by recruiting more motor units.
3) is greatest when the muscle is between 100 and 120% of its optimal resting length.
4) is increased by summation.

Answer 42

all of these are true

Question 43

Which type of smooth muscle contains gap junctions through neighboring cells and allows for the muscle to act as a syncytium, or single unit?

Visceral or Multiunit?

Answer 43

Visceral

Question 44

All muscle cells contain actin and myosin. True or false?

Answer 44

True

All muscle contraction is based on the interaction between actin and myosin but different types of muscle have different forms of myosin.

Question 45

The muscle fibers of skeletal muscle are electrically coupled so that one nerve fiber can control the activity of several muscle fibers. True or false?

Answer 45

False

Skeletal muscle fibers act independently of each other unlike cardiac and visceral smooth muscle cells, which are linked by gap junctions.

Question 46

Describe receptor potentials

Answer 46

Graded receptor potentials are translated into action potentials of various frequencies, depending on the size of the stimulus.

Receptor potentials are graded (not all or nothing) and the action potential does not change in strength (i.e. amplitude). Instead, large receptor potentials will result in an increase in frequency of action potentials which signals to the central nervous system that a large stimulus is present.

Question 47

Many receptor potentials, for example those involved in hearing and muscle or joint sensation, are initiated through which of the following channels?

Answer 47

Mechanically gated ion channels.

Question 48

A receptor that undergoes fast adaption would be expected to:

Answer 48

Stop signaling shortly after a continuous stimulus was delivered.

Question 49

The sensation of pain resulting from mechanical disruption is initially detected by binding of __________ , which results in release _____________, that in turn triggers the release of ________________ .

Answer 49

Bradykinin is a pain inducing substance that leads to release of substance P causing mast cells to release histamine.

Question 50

The patellar reflex is able to excite/inhibit different muscle groups because:

Answer 50

Afferent neurons sending stimulus information synapse directly on motor neurons and also excite inhibitory interneurons

Question 51

UMN (upper motor neuron) damage tends to result in muscle _________ while LMN (lower motor neuron) damage tends to result in muscle _________ .

Answer 51

LMNs must innervate muscle to cause tone; if they are lost, the muscle is inactive; When descending UMNs are damaged, the muscle is hyperexcited, contributing to spasticity.

Question 52

The taste receptors that are excited by direct movement of ions include:

Answer 52

Salty

Question 53

The taste receptors that are excited by a G-protein coupled mechanism include:

Answer 53

Sweet

Sweet receptors use GPCRs; sour receptors may vary but typically use either H+ channels or Transient receptor potential (TRP) receptors.

Question 54

G protein signaling through which alpha subunit is thought to initiate the sense of taste in taste buds that signal through such a mechanism?

Answer 54

GalphaQ

Question 55

Each olfactory receptor cell:

Answer 55

Expresses a single type olfactory receptor and converges onto neurons specific for that type of receptor in the olfactory bulb.

Question 56

Movement of stereocilia in the following direction results in increased receptor potential:

Answer 56

Shortest to tallest

An ion channel is located at the base of the tip link and movement of the stereocilia towards the tallest pulls these channels open, while deflection towards the shortest allows the channels to fully close.

Question 57

The photoreceptor cell receptor potential is:

Answer 57

Hyperpolarizing in response cessation of inward movement of Na+

Question 58

The hair cell receptor potential is:

Answer 58

Depolarizing in response to inward movement of K+

Question 60

Describe the physiological cause of Muscular dystrophy (Duchenne and Becker)

Answer 60

• Muscular dystrophy (Duchenne and Becker)