Hist: Skeletal muscle and nerve tissue

Question 1

Skeletal muscle

Answer 1

makes up the skeletal muscle system
striated and voluntary movement and posture
makes up 40 percent of the body mass

Question 2

Cardiac muscle

Answer 2

Heart, striated and involuntary

pumps blood through the CV system

Question 3

Smooth muscle

Answer 3

Non-striated and involuntary
visceral organ tone and movement, walls of hollow viscera, and blood vessels
does vasoconstriction and dilation

Question 4

How does contraction occur?

Answer 4

thin (actin) microfilaments and thick (myosin) filaments organize into structures called myofibrilsin the cytopasm
when they slide past each other contraction occurs

Question 5

what are the three layers of Connective tissue that organizes the myofibers into skeletal muscle?

Answer 5

Endomysium: separates myofibers
Perimysium: separates fascicles
Epimysium: Surrounds the entire muscle

Question 6

Where is the nuclei located in a skeletal muscle cell

Answer 6

multinucleated cylinders

nuclei are located in the periphery of the cell and the cytoplasm is primarily occupied by myofibrils

Question 7

What is the basic structural unit of a myofibril

Answer 7

sarcomere consisting of a thin actin and thick myosin

Question 8

what are the sleeves around the myofibril and what are their purpose

Answer 8

Sacrolemma and sarcoplasmic reticulum: sereve as Ca2+ storage and sleeves around each myofibril

Question 9

what are Transverse tubules

Answer 9

(t-tubules) and they are invaginations of the sacrolemma

help with transmission of action potentials and regulating cellular calcium levels

Question 10

Terminal cisternae

Answer 10

dilated ends of the sarcoplasmic reticulum and they release the Calcium to trigger the muscle contraction

Question 11

Structure of a sarcomere: Z line

Answer 11

Anchor site for actin (thin) filaments

Question 12

Structure of a sarcomere: I band

Answer 12

Only contains actin filaments

Question 13

Structure of a sarcomere: M-line

Answer 13

Anchor site for thick myosin filaments

Question 14

Structure of a sarcomere: H-zone

Answer 14

contains only thick myosin filaments

Question 15

Structure of a sarcomere: A-band

Answer 15

overlap of thick and thin filaments plus the H-zone

Question 16

Sliding filament mechanism

Answer 16

during muscle contraction:
the thin filaments slide past the thick filaments toward the center of the sarcomere
this brings the Z lines close together

every myofibril in a muscle cell shortens at the same time and thus the entire muscle contracts

The thin and thick filaments do not change length they just change the degree they overlap

Question 17

Tropomyosin

Answer 17

runs in the groove formed by F actin strands and it will bind to the troponin complex

Question 18

Troponin 3 types

Answer 18

Troponin T: Binds the complex to tropomyosin

Troponin I: inhibits the binding of myosin to actin

Troponin C: binds calcium

Question 19

Skeletal Muscle Fibers: Type I fibers

Answer 19

slow oxidative
contains slow ATPase, red due to high myoglobin
contractions slower and less powerful
contract for long periods of time without fatigue

Question 20

Skeletal Muscle Fibers: Type IIa fibers

Answer 20

Oxidative-glycolytic
largest and most prevalent
intermediate ATPase and provides power
Primarily aerobic - intermediate fatigue

Question 21

Skeletal Muscle Fibers: Type IIb fibers

Answer 21

Fast gycolytic
Fast ATPase produces fast contractions
largely anaerobic
rapid fatigue
lower myoglobin content

Question 22

Neuroglia

Answer 22

Neuron supporting cells

much smaller than the neuron

Question 23

Neuron

Answer 23

specialized for conduction of electrical impulses
cell body- process the electrical information
cell processes:
dendrites: carry electrical signal toward the nerve cell body
axon: 1 per cell and they carry the electrical signal away from the nerve cell

Question 24

Nissl substance

Answer 24

cluster of staining in the neurons that show the abundant rough endoplasmic reticulum that takes up the stain

reflects the need to make lots of neurotransmitters and protein to maintain the neuron

Question 25

3 classes of neurons

Answer 25

Multipolar: Many dendrites and one axon
Bipolar: one dendrite and one axon
Unipolar: one cell process from which branches a single axon and single dendrite

Question 26

how do schwann cells and satellite cells interact with the neuron

Answer 26

Satelitte cells surround the cell body of the neuron
Schwann cells surround the nerve fiber by wrapping its self around multiple times, even unmylinated fibers but just not as many times

Question 27

how does myelination help the transmission signal

Answer 27

creates nodes that allows for the signal to jump from node to node making the signal move much faster

Question 28

what are the three connective tissues that surround a peripheral nerve

Answer 28

Endoneurium: CT between axons
Perineurium: CT surrounding clusters of axons forming fascicles
Epineurium: CT surrounding several nerve fascicles

Question 29

What are the parts to the chemical synapse

Answer 29

Pre synaptic knob (axon terminal)
synaptic cleft
Pre synaptic membrane
Post synaptic membrane

Question 30

Neuromuscular junction

Answer 30

Every skeletal muscle cell recieves an axon terminal where they release the neurotransmitters

the neurotransmitter causes changes in the sarcolemma that excite the muscle
this travels down the T Tubules that initicat the fiber contraction at the terminal cisterna (release of calcium)

Question 31

Muscle spindle receptors:

Answer 31

monitor changes in length, rate of change, and tension of muscle
Intrafusal fibers: inside the muscle spindle
Extrafusal fibers: oustside the spindle, alpha motor fibers

Question 32

Intrafusal fibers:

Answer 32

Nuclear bag fibers: wraps near center of cell and detect changes in length and degree of tension, Type Ia

Nuclear chain fibers: wraps end of cell and detects static muscle length Type II

Question 33

Golgi tendon organs:

Answer 33

encapsulated receptors within myotendinous junctions that sense tension within the tendon