Muscular Tissue (Smooth Muscle)

Question 1

regulatory protein that facilitates contraction in smooth muscles

Answer 1

calmodulin

Question 2

sarcoplasmic structure that attaches to the sarcolemma and shortens the muscle as thin filaments slide past thick filaments

Answer 2

dense body

Question 3

process in which one cell splits to produce new cells

Answer 3

hyperplasia

Question 4

subset of a cross-bridge in which actin and myosin remain locked together

Answer 4

latch-bridges

Question 5

cell that triggers action potentials in smooth muscle

Answer 5

pacesetter cell

Question 6

relaxation of smooth muscle tissue after being stretched

Answer 6

stress-relaxation response

Question 7

enlargement of neurons that release neurotransmitters into synaptic clefts

Answer 7

varicosity

Question 8

Smooth muscle found in the walls of visceral organs

Answer 8

visceral muscle

Question 9

named as such because the cells do not have striations

Answer 9

Smooth muscle

Question 10

It is present in the walls of organs that contain a lumen like the urinary bladder, uterus, stomach, and intestines, and in the walls of large vascular tubes, such as the arteries and veins of the circulatory system.

Answer 10

Smooth muscle

Question 11

(6) Smooth muscles are present in these organ walls that contain a lumen.

Answer 11

urinary bladder
uterus
stomach
intestines

in the walls of large vascular tubes, such as the arteries and veins of the circulatory system

Question 12

These tracts contain smooth muscle.

Answer 12

The tracts of the respiratory, urinary, and reproductive systems

Question 13

Smooth muscle is also present in this organ, where it functions to change the size of the pupil

Answer 13

Eye

Question 14

Smooth muscle is also present here, where it causes hair to stand erect in response to low temperatures or fear. ).

Answer 14

skin

Question 14

Smooth muscle is also present here, where it causes hair to stand erect in response to low temperatures or fear.

Answer 14

skin

Question 15

It is referred to as an involuntary muscle since it is not under voluntary control. In certain locations, such as the walls of visceral organs, stretching the muscle can trigger its contraction (the stretch-relaxation response)

Answer 15

Smooth muscle

Question 16

Smooth muscle contraction relies on the presence of ___________ similar to skeletal and cardiac muscle.

Answer 16

Ca++ ions

Question 17

The influx of extracellular Ca++ ions, which diffuse into the sarcoplasm to reach a protein called __________.

Answer 17

calmodulin

Question 18

A small amount of calcium remains in the ____________ to maintain muscle tone and keep the cells contracted to a small degree.

Answer 18

sarcoplasm

Question 19

Functions of smooth muscle

Answer 19

Moves food, urine, and reproductive tract secretions
Controls diameter of respiratory passageways
Regulates diameter of blood vessels

Question 20

Smooth muscle is not under voluntary control; thus, it is called ___________.

Answer 20

involuntary muscle

Question 21

Enumerate the triggers for smooth muscle contraction

Answer 21

hormones;
neural stimulation by the ANS;
and local factors
Also, stretch-relaxation response

Question 22

In certain locations, such as the walls of visceral organs, this one can also trigger the contraction.

Answer 22

stretching the muscle (stretch-relaxation response)

Question 23

series of neurotransmitter-filled bulges

Answer 23

varicosities

Question 24

It releases neurotransmitters into the synaptic cleft. Also, visceral muscle in the walls of the hollow organs (except the heart) contains pacesetter cells.

Answer 24

varicosity

Question 25

It can spontaneously trigger action potentials and contractions in the muscle.

Answer 25

pacesetter cell

Question 26

It is aseries of axon-like swelling, from autonomic neurons form motor units through the smooth muscle.

Answer 26

varicosities or “boutons,”

Question 27

These are spindle-shaped (wide in the middle and tapered at both ends, somewhat like a football) and have a single nucleus; they range from about 30 to 200 μm (thousands of times shorter than skeletal muscle fibers), and they produce their own connective tissue, endomysium.

Answer 27

Smooth muscle fibers

Question 28

Although they do not have striations and sarcomeres, they do have actin and myosin contractile proteins and thick and thin filaments. These thin filaments are anchored by dense bodies.

Answer 28

smooth muscle fibers

Question 29

It is analogous to the Z-discs of skeletal and cardiac muscle fibers and is fastened to the sarcolemma. Calcium ions are supplied by the SR in the fibers and by sequestration from the extracellular fluid through membrane indentations called calveoli.

Answer 29

dense body

Question 30

Smooth muscle is organized in two ways

Answer 30

a. as single-unit smooth muscle
b. as multiunit smooth muscle

Question 31

It has its muscle fibers joined by gap junctions so that the muscle contracts as a single unit.

Answer 31

Single-unit muscle

Question 32

This type of smooth muscle is found in the walls of all visceral organs except the heart (which has cardiac muscle in its walls), and so it is commonly called visceral muscle.

Answer 32

Single-unit muscle

Question 33

It produces slow, steady contractions that allow substances, such as food in the digestive tract, to move through the body.

Answer 33

visceral smooth muscle

Question 34

It is rarely possess gap junctions, and thus are not electrically coupled. As a result, contraction does not spread from one cell to the next, but is instead confined to the cell that was originally stimulated.

Answer 34

Multiunit smooth muscle cells

Question 35

Stimuli for multiunit smooth muscles come from _____________ but not from stretching. This type of tissue is found around large blood vessels, in the respiratory airways, and in the eyes.

Answer 35

autonomic nerves or hormones

Question 36

Unlike other muscle, smooth muscle can also divide to produce more cells, a process called ____________.

Answer 36

hyperplasia

Question 37

This can most evidently be observed in the uterus at puberty, which responds to increased estrogen levels by producing more uterine smooth muscle fibers, and greatly increases the size of the myometrium.

Answer 37

Hyperplasia

Question 38

These are nonstriated, but their sarcoplasm is filled with actin and myosin.

Answer 38

smooth cells

Question 39

Single-unit smooth muscle in the walls of the viscera, which has a stress-relaxation response that permits muscle to stretch, contract, and relax as the organ expands.

Answer 39

visceral muscle

Question 40

It do not possess gap junctions, and contraction does not spread from one cell to the next.

Answer 40

Multiunit smooth muscle cells