A&P 1 Lab- Exam 3 Practical (Muscle Physiology)

From deep to superficial, name the three types of connective tissue sheaths of a skeletal muscle

Endomysium, Perimysium, Epimysium

Why are the connective tissue wrappings of a skeletal muscle important?

Support and bind the muscle fibers together, increase the strength of the muscle and provide a round of entry, and exit nerves and blood vessels that serve the muscle.

For skeletal muscle fibers to contract, they must be excited by motor neurons. However, the electrical impulse cannot pass directly from a neuron to the skeletal muscle fibers to excite them. Just what does pass from the neuron to the muscle fibers, and what effect does it produce?

Acetylcholine interacts with muscle cell receptors after diffusing from the axon into the synaptic cleft. More sodium ions can enter muscle fibers due to a shift in permeability.

Label A

Tendon

Label B

Epimysium

Label C

Endomysium

Label D

Muscle Fiber

Label E

Endomysium

Label F

Fascicle

Label G

Perimysium

Label H

Bone

Label number 1

Nuclei

Label number 2

Dark A Band

Label number 3

Light I Band

Label number 4

Muscle Fiber

Label number 5

Sacroleema

Label number 6

Mitochondrion

Label number 7

Dark A Band

Label number 8

Light I Band

Label number 9

Nucleus

Label number 10

Myofibril

Label number 11

Z Disc

Label number 12

H Zone

Label number 13

Thin filament

Label number 14

Thick Filament

Label number 15

I Band

Label number 16

A Band

Label number 17

M Line

Label number 18

Elastic Filaments

Label number 19

Outer Edge of A Band

Motor Unit Recruitment

When multiple muscle fibers are stimulated by a single motor neuron. Slight contractions cause few fibers to contract.

Threshold Value

This is BEFORE a muscle contracts and the impulse that triggers the contraction must be above the threshold value.

Graded Response

The muscles gradually increase from slight to more forceful contractions.

Summation

The rise in contraction force, either increasing the frequency of impulses to a single muscle fiber or boosting the stimulus to an expanding number of muscle fibers might cause this.

Incomplete Tetanus

A sequence of contractions brought on by a muscle receiving repeated, fast stimulation.

Complete Tetanus

When the frequency of the stimulus increases, a muscle’s smooth contractions merge.

Aponeurosis

Connective tissue is a broad, flat layer that joins to bones or other muscles.

Agonist

Sometimes referred to as the prime mover, this is the main muscle that contracts to produce a particular movement.

Antagonist

Muscle resists the agonist’s action by relaxing or lengthening to permit the agonists movement.

Synergist

Muscle used to help the agonist move.

Fixatior

Muscle keeps other joints from moving unintentionally by stabilizing its origin.

Fascia

Fibrous connective tissue that envelops & sustains bones, muscles, and organs.

Label 1

Presynaptic Terminal

Label 2

Synaptic Vesicles

Label 3

Postsynaptic Membrane (sacroleema)

Label 4

Synaptic Cleft