Exam 3 short answer Flashcards

1
Q

Know the 8 functions of muscles.

A
  • Movement of bones
  • Maintaining posture and body position
  • Stabilizing joints
  • Heat generation
  • Supports soft tissues
  • Protects organs
  • forms valves
  • controls pupil size
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2
Q

Define origin and insertion.

A

Insertion – movable bone
Origin – immovable (less movable) bone

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3
Q

Define sarcolemma, myofibrils and sarcoplasmic reticulum

A

Sarcolemma = plasma membrane on skeletal muscle fiber
Myofibrils: basic rod-like organelle of a muscle cell
sarcoplasm reticulum: Network of smooth endoplasmic reticulum surrounding each myofibril

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4
Q

Define sarcomere, T tubules, triad

A

Sarcomere: region between two successive Z discs
t-tubules: Continuations of sarcolemma
triad:

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5
Q

Define tropomyosin and troponin.

A

two proteins that are present on the thin filaments of the muscle cells and help in the contraction of muscles.
troponin promotes muscle contraction, tropomyosin blocks muscle contraction.

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6
Q

What is the function of the sarcoplasmic reticulum?

A

Stores and releases Ca2+

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7
Q

What structure increases the surface area of the muscle fiber?

A

T-Tubules

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8
Q

Understand the sliding filament model of contraction.

A
  1. calcium ions are released by the sarcoplasmic reticulum in the actin filament.
  2. Calcium ions cause cross bridges (bond) to form
  3. Myosin head slides
  4. skeletal muscle contraction has occurred
  5. Cross bridge breaks
  6. troponin resets the actin to its original position
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9
Q

What occurs during a cross bridge cycle? Be able to recognize the steps.

A
  1. the cross bridge is formed by energized myosin heads that attach to actin myofilaments
  2. power working stroke: myosin head pivots and pulls thin filament towards M line
  3. cross bridge detaches- ATP attaches to myosin head and cross bridge detaches.
  4. Cocking of myosin head: energy from hydrolosis of ATP cocks myosin head into high energy state.
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10
Q

What is excitation contraction coupling?

A
  • Action potential propagated along sarcolemma
  • Intracellular Ca2+ levels must rise briefly
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11
Q

Know the components of a neuromuscular junction:

A

a. Axon terminal (presynaptic axon)
b. Synaptic cleft: gap between the pre- and postsynaptic cells
c. Sarcolemma (postsynaptic membrane; junctional folds)

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12
Q

Understand the steps which occur at the NMJ during a nerve stimulus:

A

ACh is broken down by acetylcholinesterase. AChE

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13
Q

Describe the cross bridge cycle and its components
a. Why is calcium important?
b. What is the function of ATP on the myosin head? .

A

a. Continues as long as Ca2+ signal and adequate ATP present
b. Cross bridge detachment—ATP attaches to myosin
head and cross bridge detaches

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14
Q

List the 4 patterns of fascicles. Provide an example for each.

A

– Circular: orbicularis oris
– Convergent: pectoralis major
– Parallel: sartorius
– Pennate: rectus femoris

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15
Q

What is the most common type of “lever” in the body; provide an example.

A

third class level.
example: forceps and most skeletal muscles

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16
Q

Describe the relationship between an agonist and an antagonist muscle.

A

Prime mover (agonist): Major responsibility for producing specific movement
Antagonist: Opposes or reverses particular movement
- agonist and antagonist are located on opposite sides of joint across which they act

17
Q

name the neuroglia cells

A

CNS: microglial cells, ependymal cells, olingodendrocytes.
PNS: Satellite cells, schwann cells

18
Q

Functions of CNS cell

A

Astrocytes: -maintain blood-brain barrier, structural framework, repair damaged neural tissues
Microglial:Engulf debris, waste products, and pathogens
Ependymal:Produce CSF, Provides protection to neural tissue, Transports nutrients, wastes,
Oligodendrocytes:–Form myelin sheath around the axon of CNS neurons

19
Q

Functions of cells in PNS

A

Satellite cells: -maintain blood-brain barrier, structural framework, repair damaged neural tissues
Schwann cells: Form myelin sheath around the axon of CNS neurons

20
Q

What is a resting membrane potential? What is the charge inside the cell?

A

A cell membrane at rest and is negatively charged. The inside of a cell membrane is more negative than outside. -70 mV

21
Q

Define depolarization, hyperpolarization, repolarization.

A

deplarization:generation and propagation of an
action potential
hyperpolarizations: polarization more negative than the resting potential
repolarization: restoring electrical conditions of
RMP

22
Q

What is meant by “all or none” in regards to action potentials.

A

An Action Potential either happens completely, or it does not happen at all.

23
Q

Know what occurs at each phase of the action potential graph: resting state, depolarization,
repolarization, hyperpolarization.

A

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