Nerve, Muscle, Synapse Lecture 5 Flashcards Preview

Vanders Human Physiology (PHYSL 210) > Nerve, Muscle, Synapse Lecture 5 > Flashcards

Flashcards in Nerve, Muscle, Synapse Lecture 5 Deck (39)
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1
Q

_______ neurons are always excitatory

A

Afferent = release glutamate

2
Q

What are the three types of muscle?

A

Smooth

Cardiac

Skeletal

3
Q

_____ muscle is found in all organs of the body and their contractions act to reduce the size of structures

A

Smooth muscle is found in all organs of the body and their contractions act to reduce the size of structures

4
Q

What are four functions of smooth muscle?

Voluntary or involuntary?

A
  1. Regulates flow of blood through arteries
  2. Moves food through GI tract
  3. Expels Urine from the bladder
  4. Regulates the flow of air through the lungs

Involuntary

5
Q

Cardiac Muscle:

  • _____ muscle found in the walls of the ______
  • Propels blood into the _____ and through the _____ of the circulatory system
  • _______ control
A

Cardiac Muscle:

  • striated muscle found in the walls of the heart
  • Propels blood into the heart and through the blood vessels of the circulatory system
  • involuntary control
6
Q

_______ muscle is attached to the skeleton and is also called striated muscle

A

skeletal muscle is attached to the skeleton and is also called striated muscle

7
Q

Skeletal muscle is under _______ control

A

voluntary

8
Q

Each muscle cell is surrounded by _______

A

endomysium

9
Q

_______ surrounds each muscle fiber (cell) and electrically isolates the muscle fibers from one another

A

endomysium surrounds each muscle fiber (cell) and electrically isolates the muscle fibers from one another

10
Q

Skeletal muscles are electrically insulated from each other by ______

A

endomysium

11
Q

In order for skeletal muscle cells to contract, each cell must be stimulated by a process of a ________

A

Motor Neuron

12
Q

Motor neurons leave the spinal cord through the:

A

Ventral Horn

13
Q

Each ______ neuron innervates a number of muscle cells = impossible to contract just one muscle cell

A

Each efferent neuron innervates a number of muscle cells = impossible to contract just one muscle cell

14
Q

A motor neuron, its axon and all the muscle fibers it activates makes up the:

A

Motor unit

15
Q

The ______ is the functional unit of the motor system and represents the SMALLEST increment in force that can be generated

A

Motor Unit

16
Q

What is the neuromuscular junction

A

Where the nervous system meets the muscle

17
Q

Neuromuscular junction we have ______-gated chemical synaptic transmission with the post-synaptic cell being the: _____

A

Neuromuscular junction we have directly-gated chemical synaptic transmission with the post-synaptic cell being the: muscle cell (fibre) HAS ONLY ONE SYNAPSE

18
Q

The region of the muscle fibre plasma membrane that lies directly under the terminal portion of the axon is called:

A

the motor end plate

19
Q

What is the neurotransmitter used by the efferent (motor) neurons?

A

Acetylcholine - excitatory

20
Q

Acetylcholin binds to ______ receptors

A

Ionotropic receptors

21
Q

Ionotropic Receptors: receptors that form _______following the binding of a ______; “______-_______”

A

Ionotropic Receptors: receptors that form ion channels following the binding of a ligand; ligand-gated ion channels

22
Q

When acetylcholine binds to its receptors it generates a ________of the post-synaptic cell (muscle cell) = opens voltage gated ___ channels

A

When acetylcholine binds to its receptors it generates a local depolarization of the postsynaptic cell (muscle cell) = opens voltage gated Na+ channels

23
Q

What are 3 Differences between synaptic transmission at a neuromuscular junction and a central synapse?

A
  1. One AP in motor neuron generates one AP in muscle cell (summation required in CNS; no summation in muscle)
  2. Each muscle fibre is only innervated by one presynaptic cell
  3. No inhibitory transmitters: Only acetylcholine = always excitatory
24
Q

The extracellular space is ______ charged with respect tot he intracellular space

A

The extracellular space is Positively charged with respect tot he intracellular space

25
Q

The ______ of muscle are extracellular space = positively charged with respect to intracellular space

A

The Transverse Tubule (T-tubule) of muscle are extracellular space = positively charged with respect to intracellular space

26
Q

As sodium rushes into the muscle cell it generates an ____

A

Action Potential

27
Q

The ______ surrounds each myofibril within the muscle cell. It is loaded with calcium

A

Sarcoplasmic Reticulum

28
Q

The action potential causes the release of Ca2+ from the _______

A

Sarcoplasmic reticulum

29
Q

_______ is the neurotransmitter used at the neuromuscular junction

A

Acetylcholine

30
Q

How many neuromuscular junctions are there per muscle cell?

A

ONE

31
Q

Compare excitation-contraction coupling in Skeletal muscle to Cardiac Muscle:

A
  • Cardiac muscle:
    • L-type Ca2+ channel (modified dihydropyridine receptor)
      • voltage-gated Ca2+ channel
      • Calcium binds to Ryanodine receptor (in SR) - ryanodine receptor opens = flows out of sarcoplasmic reticulum
      • No physical coupling
    • Calcium-dependent calcium release
  • Skeletal muscle
    • Physical coupling between dihydropyridine receptor (DHP) and ryanodine receptor via foot process
    • opens calcium channel in sarcoplasmic reticulum
32
Q

Myofibrils are comprised of the contractile elements:

A

Actin and Myosin (protein filaments)

33
Q

The sarcomere is bound on either side by ____ lines

A

Z

34
Q

What is the H zone?

A

Gap between the thick filaments in the sarcomere

35
Q

Although the sarcomere shortens, the length of each _____ does not change. However, the width of the ___ zone changes

A

Although the sarcomere shortens, the length of each myofilament does not change. However, the width of the H zone changes

36
Q

During muscle contraction, the sarcomere _____ and the H-zone becomes _____

A

During muscle contraction, the sarcomere shortens and the H-zone becomes narrower

37
Q

Events at the Neuromuscular Junction

  1. The neurotransmitter _______ contained within vesicles is released via ________ into the ______. Additionally, ____ ions are pumped out of the axon terminal
A

Events at the Neuromuscular Junction

  1. The neurotransmitter acetylcholine contained within vesicles is released via exocytosis into the synaptic cleft. Additionally, Ca2+ ions are pumped out of the axon terminal
38
Q

Events at the Neuromuscular Junction

  1. The depolarization of the ________ initiates an action potential which propagates along the ______ in all directions and down the ______
A

Events at the Neuromuscular Junction

  1. The depolarization of the Motor End Plate initiates an action potential which propagates along the Sarcolemma in all directions and down the T-Tubules
39
Q

Events at the Neuromuscular junction:

  1. Action potential causes the release of Ca2+ from the _______ into the cytosol
A

Events at the Neuromuscular junction:

  1. Action potential causes the release of Ca2+ from the terminal cisternae into the cytosol