Lecture notes muscle 2 nervous Flashcards Preview

Human Anatomy > Lecture notes muscle 2 nervous > Flashcards

Flashcards in Lecture notes muscle 2 nervous Deck (37):
1

What are muscle proteins?

Myofilaments: thick and thin
Thick filament:myosin, a swivel headed protein chain
Thin filament:Actin, tropomyosin, troponin (proteins!): Double strand of actin plus strands of tropomyosin.

2

Troponin holds

The tropomyosin in place

3

A Bands are

(dark) includes H zone, M
line & zone of (thin & thick filament) overlap

4

I Bands are

(light); the region between the A band &
Z line containing primarily thin filaments

5

Z line functions as

The connecting framework for
the thin filaments and defines the borders of the sarcomere (from Z line to Z line)

6

H zone or H band, is also lighter since it has

Thick filaments only & the M line running down
the center

7

What are the events of muscle contraction?

Divided into two parts
1. Message (impulse) travels from CNS to sarcomere- conduction
2. Proteins (Actin & Myosin) move relative to each other- “sliding filament”-
contraction...

8

Events of conduction

Nerve impulse
• Neuromuscular junction
• ACH across the synaptic gap (cleft)
• Stimulates action potential on sarcolemma
• Down T-tubules
• Ca++ release from terminal cisternae

9

Ca++ release begins events of?

Contraction

10

What is the current model of muscle contraction?

The sliding filament theory

11

How are muscle fibers and neurons similar?

1) Both their membranes can conduct action potentials
2) They both show an all-or-nothing response.
3) They both must reach a threshold level to
trigger an action potential...

12

Motor units are

• One neuron and all the muscle cells it
contacts.
• Allows for fine and gross muscle control
• Less cells per motor unit = fine control – Eye muscles
• Muscles of the legs = more cells per motor unit...

13

Fast fibers v. slow fibers

Fast fibers
• quick to contract • Fatigue easily
• Lack myoglobin (anaerobic) • White in color
• Most fibers are Fast or White fibers
Slow fibers
• can sustain contraction • Have myoglobin and extensive blood supply (aerobic)
• Red in color = Red fibers
• For example; Posture muscles...

14

Intermediate fibers are?

• Moderate endurance
• Red in color
• Aerobic
• #s depend upon exercise!
• Fast fibers become intermediate fibers when used heavily

15

Atrophy is

• Loss of muscle mass
• Lack of use
• Loss of proteins
• May result in cell loss
• Never regain those cells

16

Hypertrophy

• Exercise
• Increase in mass
• Not increase in fibers (cells)! • More myofibrils
• More mitochondria
• More blood supply
• More glycogen!

17

The nervous system is divided into two parts

The central nervous system (CNS) and Peripheral nervous system (PNS)

18

The central nervous system (CNS) is

Brain (cerebrum, cerebellum, brainstem) & Spinal cord

19

The peripheral nervous system (PNS) is

Everything else that conducts nerve impulses outside of the brain & spinal cord (cranial & spinal nerves; ganglia)

20

Fibers, cell bodies, and myelin for CNS

*Fibers bundled as tracts
*Cell bodies in nucleus
*Myelin by oligodendrocytes



21

Fibers, cell bodies, and myeline for PNS

*Fibers bundled as nerves
*Cell bodies in ganglion
*Myelin by neurolemmocytes


22

From senses to CNS

Sensory

23

From CNS to muscle or gland

Motor

24

"Outer body"

Somatic

25

Internal organs

Visceral

26

Involuntary

Autonomic

27

Structural and functional unit of the nervous system

Neuron

28

What are the anatomical types of neurons?

1) Unipolar
2) Bipolar
3) Multipolar

29

Unipolar is

Cell body off to the side; sensory neurons

30

Bipolar is

A single dendrite & a single axon arising from opposite poles of the cell body; more rare; special senses

31

Multipolar is

The most common type in the CNS; several dendrites & a single axon that may have one or more branches; motor neurons

32

Sensory are what types of neurons

Unipolar

33

Motor are what type of neurons?

Multipolar

34

Interneuron (association) is

Located entirely in the CNS

35

Nerve impulse is

*Also called an Action Potential.
*Movement of an electrical charge along the plasma membrane of a neuron
*The result of a change in voltage on either side of the membrane
*All-or-nothing
*Threshold
*Speed is affected by size of fiber
*Speed is affected by insulation of axons


36

Resting potential is

-70 mv (millivolts) because the difference between the sides of the membrane due to ion pumps and diffusion

37

Action potential is

An abrupt, brief reversal “depolarization” It moves like a wave down the axon to the terminal knob. The “nerve impulse."