For exam 2 Lecture 2

Question 1

Muscular System

Answer 1

The driving force, the power behind movement, is muscle tissue

Question 2

What are the three kinds of muscle tissue?

Answer 2

Skeletal, Cardiac, and Smooth

Question 3

How do the three kinds of muscle tissue differ?

Answer 3

Differ form one another in their microscopic anatomy, location, and control by the nervous and endocrine system.

Question 4

Skeletal muscle MUST be stimulated and what stimulates it?

Answer 4

The Central Nervous System

Somatic to be specific

Question 5

What CNS controls Cardiac and Smooth muscle?

Answer 5

Autonomic

Question 6

Muscular system properties?

Answer 6

Contractility
Excitability (or Irritability)
Extensibility
Elasticity

Question 7

Which of the four muscle properties are involved in movement?

Answer 7

ALL four of them

Question 8

The ability to contract or shorten is?

Answer 8

Contractility

Question 9

What is excitability?

Answer 9

The capacity to receive and respond to stimulus.

Question 10

The ability to be stretched.

Answer 10

Extensibility

Question 11

Elasticity is?

Answer 11

The ability to return to original shape after being stretched or contracted.

Question 12

Why is the skeletal muscle so named?

Answer 12

It is attached primarily to bones and it moves parts of the skeleton

Question 13

Skeletal muscle is called striated because?

Answer 13

Altering light and dark bands are visible when the tissue is examined under a microscope.

Question 14

How are the striations produced in skeletal muscle?

Answer 14

By characteristic arrangement of contractile proteins, myosin and actin

Question 15

T:F Skeletal muscle is a voluntary muscle.

Answer 15

True

It can be made to contract and relax by conscious control?

Question 16

The sheath of connective tissue surrounding the muscle is?

Answer 16

Epimsium

Question 17

Fascicle are?

Answer 17

A bundle or cluster of muscle fibers.

Question 18

A sheath of connective tissue surrounding each fascicle is?

Answer 18

Perimysium

Question 19

Another name for muscle cell is?

Answer 19

Muscle Fiber

Question 20

Sarcolemma is?

Answer 20

Plasma membrane of a muscle cell (fiber)

Question 21

Myofibril is?

Answer 21

Threadlike structure, running longitudinally through a muscle fiber.

Question 22

What are myofibrils made up of?

Answer 22

Thick filaments (myosin) and thin filaments (actin, troponin, tropomyosin). Myofilaments.

Question 23

How are myofilaments arranged?

Answer 23

In sarcomeres

Question 24

The basic contractile unit of striated muscle fibers are?

Answer 24

Sarcomere

Question 25

Myosin, actin, troponin, tropomyosin are all?

Answer 25

Myofilaments

Question 26

Smooth muscle is lacking which myofilament?

Answer 26

Troponin

Question 27

Normally skeletal muscle is attached to bone at both ends by means of tendons, what are the exceptions to this?

Answer 27

External sphincter of the bladder | diaphragm

Question 28

T:F Each muscle fiber has one nucleus.

Answer 28

False | Each muscle fiber has many nuclei, as well as mitochondria and other organelles.

Question 29

Scattered satellite cells?

Answer 29

Lie between the endomysium and the muscle fibers. The function in repair of minor damage muscle tissue.

Question 30

Cardiac muscle is only found in?

Answer 30

The heart

Question 31

How does cardiac differ from skeletal muscle even though it is striated aswell?

Answer 31

The myocardial cells are shorter, branched, and intimately interconnected to form a continuous fabric

Question 32

Intercalated discs which are characteristic of heart muscle are?

Answer 32

Special areas of contact between adjacent cell in heart muscle

Question 33

T:F Gap junctions of intercalated discs couple myocardial cells together mechanically and electrically.

Answer 33

True | All cells in the myocardium are electrically joined by gap junctions, the myocardium behaves as a single unit.

Question 34

T:F The heat can produce a graded contraction by varying the number of cells stimulated to contract.

Answer 34

False Unlike skeletal muscle, the heart CANNOT produce a graded contraction by varying the number of cells stimulated to contract.

Question 35

T:F The stimulation of one myocardial cell in the heart will result in the stimulation of all the cells in the mass and the whole hear will contract.

Answer 35

True | Myocardium are joined electronically by gap junctions of intercalated discs. Move one and they all move

Question 36

What happens if heart cannot contract as a unit?

Answer 36

Arrhythmia

Question 37

If heart cells are damaged do they grow back?

Answer 37

No they cannot repair themselves

Question 38

If heart contractions are to its full extent for each contraction, how can the ability of myocardial cells to contract be increased?

Answer 38

Sympathetic system and stretching of the myocardial chambers.

Question 39

What are the two very distinct myocardial chambers?

Answer 39

Atria and ventricles

Question 40

What is the difference between cardiac and skeletal muscles in regards to action potential?

Answer 40

Skeletal muscle require external stimulation my somatic motor nerves before they can produce action potentials and contract Cardiac is able to produce action potential automatically.

Question 41

Cardiac action potential normally originates in a specialized group of cells called the?

Answer 41

Pacemaker

Question 42

The rate of spontaneous depolarization and thus the rate of the heart beat are regulated by?

Answer 42

Autonomic innervation

Question 43

In skeletal muscle there is a direct excitation-contraction coupling between?

Answer 43

The transverse tubules and the sarcoplasmic reticulum

Question 44

What does stimulation of the heart muscle lead to? | Also known as Ca2+ induced Ca2+ release

Answer 44

Leads to Ca2+ entry into the cytoplasm through voltage-gated channel. This Ca2+ stimulates the opening of Ca2+ release channels of the sarcoplasmic reticulum

Question 45

Transverse tubules are?

Answer 45

Small cylindrical invaginations of sarcolemma of striated muscle fiber that conduct muscle action potentials towards the center of the muscle fiber.

Question 46

Intercalated discs are?

Answer 46

Cell to cell attachment with gap junctions that aid in the conduction of muscle action potentials and desmosomes that hold the cardiac muscle fibers together

Question 47

Mechanism of contraction for cardiac and skeletal muscle?

Answer 47

Sliding filament theory

Question 48

Describe smooth muscles?

Answer 48

Cells also called fibers. Each fiber is short, spindle shaped and slender which contain only one nucleus near the center of the fiber, at its widest point.

Question 49

Why does smooth muscle lack striations?

Answer 49

The actin and myosin myofilaments are very thin and are arranged more randomly than in skeleton muscle fibers.

Question 50

What are the actin filaments attached to in the smooth muscle?

Answer 50

Dense bodies

Question 51

In smooth muscle where are the dense bodies?

Answer 51

They are distributed throughout the sarcoplasm in a network of intermediate filaments. Some are firmly attached to the sarcolemma

Question 52

T:F In smooth muscle the sarcoplasmic reticulum is poorly developed and the T tubules and Z lines are present.

Answer 52

False | In smooth muscle the sarcoplasmic reticulum is poorly developed and the T tubules and Z lines are NOT present.

Question 53

In smooth muscle the slowest contraction is thought to be due to?

Answer 53

A limited amount of ATPase activity at the crass bridges

Question 54

Two types of smooth muscle are?

Answer 54

Single unit and multiunit

Question 55

Where are the single units of smooth muscles found?

Answer 55

Found in the walls of tubes and hollow organs.

Question 56

Which is more common smooth muscle types

Answer 56

Single unit

Question 57

Smooth muscle multiunit

Answer 57

Consists of individual fibers, each with its own motor neuron terminals

Question 58

What is the difference between single unit and multiunit smooth muscles?

Answer 58

stimulation of a single unit muscle fiber causes contraction of many adjacent fibers. Stimulation of one one multiunit fiber causes contraction of only that muscle fiber

Question 59

Where are smooth muscle multiunits found?

Answer 59

Found in the walls of large arteries, bronchioles, arrector pili muscles attached to hair follicles, radial and circular muscles of the iris that adjust pupil diameter, and in the ciliary bodies that adjust focus of the lens in the eye.

Question 60

Smooth muscle single unit

Answer 60

Electrically linked by gap junctions, self excitable (myogenic activity)

Question 61

Smooth muscle multiunit

Answer 61

Innervated by the autonomic nervous system (neurogenic activity)

Question 62

T:F Sarcomeres are not present in smooth muscle cells.

Answer 62

True

Question 63

Describe smooth muscle contraction.

Answer 63

Dense bodies and intermediate filaments anchor the actin thin filaments so that when sliding occurs between myosin and actin, the cell shortens and bilges between the points where the dense bodies are attached to the sarcolemma.