Muscle Tissue (Q2,P2)

Question 1

Functional Classifications of Muscle Tissue

Answer 1

1) Skeletal muscle - attached to skeleton (40% of body weight, striations)
Moves body by moving the bones
2) Smooth muscle – squeezes fluids and other substances through hollow organs (involuntary; no striations)
3) Cardiac muscle – propels blood through the circulatory system (coiled striations for contraction)

Question 2

Movement

Answer 2

• Muscles produce movement by pulling on bones as a muscle contracts
• Movement occurs at the joint between the origin and the insertion
• Groups of muscles usually contract to produce a single movement (prime mover,synergist, antagonist)

Question 3

Posture

Answer 3

• A continuous, low-strength muscle contraction called tonic contraction (muscle tone) enables us to maintain body position
• Good posture favors best body functioning
• Skeletal muscle tone maintains good posture by counteracting the pull of gravity

Question 4

Heat Production

Answer 4

• Survival depends on the body’s ability to maintain a constant body temperature
• Fever: An elevated body temperature; often a sign of illness
• Hypothermia: A reduced body temperature
• Contraction of muscle fibers produces most of the heat required to maintain normal body temperature

Question 5

Fatigue

Answer 5

• Reduced strength of muscle contraction
• Caused by repeated muscle stimulation without adequate periods of rest
• Oxygen debt: the metabolic effort required to burn excess lactic acid that may accumulate during prolonged periods of exercise
• Labored breathing after strenuous exercise is required to “pay the debt”

Question 6

Functional Features of Muscle Tissue

Answer 6

• Contractility – long cells shorten and generate pulling force
• Excitability – electrical nerve impulse stimulates the muscle cell to contract
• Extensibility – can be stretched back to its original length by contraction of an opposing muscle
• Elasticity – can recoil after being stretched

Question 7

Skeletal Muscle

Answer 7

• Each muscle is an organ
• Consists mostly of muscle tissue
  Skeletal muscle also contains
  1) Connective tissue
  2) Blood vessels
  3) Nerves

Question 8

Connective Tissue & Fascicles of Skeletal Muscle

Answer 8

• Connective tissue sheaths bind a skeletal muscle and its fibers together
• three types: epimysium, perimysium, endomysium
• Connective tissue sheaths are continuous with tendons

Question 9

Epimysium

Answer 9

• Type of Connective Tissue of Skeletal Muscle
• dense irregular connective tissue surrounding entire muscle

Question 10

Perimysium

Answer 10

• Type of Connective Tissue of Skeletal Muscle
  -surrounds each fascicle – fibrous connective tissue (group of muscle fibers)

Question 11

Endomysium

Answer 11

• Type of Connective Tissue of Skeletal Muscle
  – a fine sheath of connective tissue wrapping each muscle cell – mostly reticular fibers

Question 12

Nerves and Blood Vessels of Skeletal Muscle

Answer 12

• Each skeletal muscle supplied by
  One nerve, One artery& One or more veins
• Nerves and vessels branch repeatedly
• Smallest nerve branches serve individual muscle fibers

Question 13

Muscle Attachments of Skeletal Muscle

Answer 13

• Most skeletal muscles run from one bone to another
• One bone will move, other bone remains fixed
• Origin: less movable attachment
• Insertion: more movable attachment
• Muscles attach to origins and insertions by connective tissue:
• 2 types, fleshy and indirect attachments

Question 14

Fleshy Attachments

Answer 14

Connective tissue fibers are short

Question 15

Indirect Attachments

Answer 15

connective tissue forms a tendon or aponeurosis

Question 16

Muscle

Answer 16

• muscle means “little mouse”
• The main tissue of the heart and walls of hollow organs
• Composes nearly half the body’s mass