1. Human Muscular System
SVHS Adv. Biology
Unit #6

2. Normal or Not???

3. Muscular System Study of muscle is known as myology.
40-50% of body weight is muscle.

4. Muscle Tissue Types Smooth Involved in internal processes.
Makes up the walls of hollow internal structures.
Involuntary

5. Muscle Tissue Types Cardiac
Forms wall of the heart and major vessels leading from the heart

6. Muscle Tissue Types Skeletal Attached to skeleton.
Responsible for skeletal movement.

7. Functions of Muscle Tissue
Producing body movement
Movement of substances in body.
Stabilizing body position.
Regulating organ volume.
Heat production.

8. Striated Muscle Connective Tissue.
Connective tissues
Superficial facia
Contains fat and is just below the skin.
Deep facia
Connective tissue
Holds muscles together.
Separates muscle bundles
Extends to form tendons

9. Striated Muscle Connective Tissue.
The entire muscle is wrapped in the epimysium

10. Striated Muscle Connective Tissue.
Muscle bundles are surrounded by facia called perimysium

11. Striated Muscle Connective Tissue.
Each muscle fiber (cell) is covered by another facia called endomysium.

12. Striated Muscle Blood supply
Muscle contraction requires large amounts of energy and so requires large amounts of nutrients and oxygen.

13. Striated Muscle Nervous Tissue
Nerve tissue
Motor neuron
Motor unit= 1 neuron stimulates 1 muscle fiber
Muscle must receive a stimulus in order to contract.
Muscle action potential: an electrical signal that stimulates a muscle to contract

14. Homework Quiz - Activity A
1- T or F Smooth muscle is involuntary and found in the walls of blood vessels.
2- T or F Cardiac muscle is not under conscious control.
3- T or F Striated muscle is voluntary and is also called
skeletal muscle.
4- Which of the following is not a function of the muscular system?
A) Creating motion
B) Moving substances in the in the body.
C) Creating body heat.
D) Sustaining the body’s posture.
E) Producing hormones for growth.

15. 5- Which of the following is not a characteristic of muscle tissue?
A) Ability to return to it’s original shape.
B) Ability to respond to a stimuli.
C) Ability to push bones to create movement.
D) Ability to shorten.
E) Ability to stretch.
6- The ability of muscle to stretch is referred to as ?
7- Muscle making up the wall of the heart is known as ?
8- Muscle making up the walls of the intestine is known as ?

16. Answers
1) True
2) True
3) True
4) E (producing hormones for growth)
5) C (ability to push bones)
6) Extensibility (ability to stretch)
7) Cardiac (makes up wall of heart)
8) Smooth (makes up wall of intestines)

17. Muscles + Bones = Lever Systems
Class I lever
fulcrum between resistance and energy.
Class II lever
Resistance between energy and fulcrum.
Class III lever
Energy is between fulcrum and resistance.

19. Skeletal Muscle Structure
Tortora pages 156
Each muscle fiber or cell is composed of subunits called myofibrils

20. Striated Muscle Structure
Tortora pages
Structure of striated muscle cell.
Sarcolemma
Sarcoplasm
Sarcoplasmic reticulum
Transverse tubules

22. Striated Muscle Structure
Tortora pages 156
Proteins of muscle are called myofilaments.
Thin protein filament is composed of:
Actin
Tropomyosin.
Thick protein myofilament is myosin.
Myosin has cross bridges.

23. Striated Muscle Structure
Tortora pages 156
Actin
Contains myosin binding site.
Site is covered by tropomyosin.
Myosin
Contains actin binding site.
Contains a binding site for ATP.

25. Striated Muscle Structure
Tortora pages 156
Sarcomeres are contracting units in muscle.
Each fiber has many myofibrils.
Each myofibril is composed of many sarcomeres.
Z lines
A band
I band
H zone

26. Tortora pages 156

27. C & D Quiz Which lever type is a distance multiplier?
Which lever type has the force exerting between the fulcrum and the load?
A muscle that decreases the angle of a joint.
A muscle that moves a bone away from the midline of the body.
A muscle that decreases the size of an opening.
A muscle that produces a downward movement.
A muscle that turns the palm downward or posteriorly.

28. Striated Muscle Structure
Motor units
Motor neuron
Muscle cell
fibers per motor neuron.
Neuromuscular junctions
Motor end plate.
Synaptic cleft.
Sarcolemma

29. Neuromuscular Junctions
Starting a muscle contraction.
Nerve impulse reaches axon terminal.
Ca++ enters the synaptic end bulb.
Vesicles move to and fuse with membrane.
Vesicle releases ACH into the synaptic cleft.

30. Neuromuscular Junctions
5) ACH diffuses across cleft and binds to ACH receptors in sarcolemma.
6) Muscle action potential is created.
7) Within 1/500 of a second ACHe inactivates ACH.
8) Muscle prepares for next muscle action potential.
Neuromuscular Junctions

33. Physiology of Contraction
Muscle action potential spreads across sarcolemma.
Reaches into the transverse tubules.
Spreads to the sarcoplasmic reticulum.
Sarcoplasmic reticulum releases Ca++

34. Physiology of Contraction
Calcium binds to tropomyosin, changing its shape.
Myosin and actin bind.
ATP is broken down to ADP .
Powerstroke occurs.

35. Striated Muscle & Relaxation
Two changes cause relaxation.
ACh broken down by Ache.
Results in no muscle action potential.
Ca++ is rapidly removed from the sarcoplasm.
Results in tropomyosin covering the myosin binding sites on the actin.

36. Striated Muscle & and Energy
Tortora
Pages 160,
ATP is needed as energy source for muscle contraction.
ATP attaches to ATP binding site on myosin head.
ATP is broken down to ADP + P.
Myosin cross bridge is energized.

37. Striated Muscle & and Energy
Ca++ removes tropomyosin.
Actin & myosin engage.
Cross bridge changes shape. (Powerstroke)
ADP is released.
ATP again attaches to binding site causing actin & myosin to disengage.
ATP is broken down causing myosin head to return to normal position.
Powerstroke repeated.

38. Energy for Muscle Contraction
Contraction is powered initially by ATP stored in the muscle.
5 second supply.
40 yards into 400 meter race.

39. Energy for Muscle Contraction
Creatine Phosphate
Energy is released from CP.
Used to make more ATP from ADP and Pi.
Supplies 15 seconds worth of energy.
22 seconds or 220 yards into race.

40. Energy for Muscle Contraction
Glycolysis
Glucose is broken down to pyruvic acid.
Occurs in sarcoplasm.
Anaerobic (does not require oxygen)
Results in lactic acid if no oxygen available.
Lactic acid causes fatigue feeling.
Provides 30 seconds worth of muscle contraction.
You are now 300 yards into race.

41. Energy for Muscle Contraction
Aerobic respiration.
Occurs in mitochondria.
Breaks down pyruvic acid.
Requires oxygen.
Results in H2O and CO2 as wastes.
Makes 34 ATP molecules.
Now you can run a marathon!!

42. Energy for Muscle Contraction
Greg LeMond’s career ended due to a mitochondrial condition.
What is he doing today?

43. Still Racing!!

45. Oxygen Debt Occurs when oxygen does not get to muscles.
Glycolysis results in lactic acid formation.
Must acquire oxygen to pay back debt.
Heavy breathing after exercise!

46. All-or-None Principle
Any given motor unit will be fully contracted or not at all.
Threshold stimulus causes contraction.
Subthreshold will not create a contraction.
Some motor units are contracted while others are not.

47. Homeostasis Oxygen Debt Muscle Fatigue Heat production
Due to lactic acid.
Paid back with oxygen.
Muscle Fatigue
Due to L.A.
Decrease in pH.
Heat production
85% of energy is released in form of heat.

48. Types of Contraction
Tortora Page 164
Different types of contractions depending on how often stimulation occurs.
A muscle twitch is a brief contraction of all muscle fibers in a motor unit due to a single nerve impulse.

49. Types of Contraction Phases of a muscle twitch Latent phase
Tortora Page 164
Phases of a muscle twitch
Latent phase
Action potential spreads across sarcolemma
Ca++ released.

50. Types of Contraction Contraction phase Power stroke.
Tortora Page 164
Contraction phase
Power stroke.
Actin and myosin slide over one another.
Muscle becomes shorter.

51. Types of Contraction Relaxation phase Actin & Myosin disengage.
Tortora Page 164
Relaxation phase
Actin & Myosin disengage.
Ca++ is actively pumped back into the sarcoplasmic reticulum.

52. Types of Contraction Refactory phase
Sarcolemma not responsive to a stimulus

53. Types of Contraction Wave Summation
Successive stimuli prior to completion of relaxation phase.
Each contraction is stronger than the previous

54. Types of Contraction Incomplete Tetanus Complete Tetanus
20 to 30 stimuli per second.
Partial relaxation
Complete Tetanus
stimuli per seconds.
No relaxation.

55. Types of Contraction Isotonic Isometric Contraction and movement
Contraction without movement

56. Skeletal Muscle Tissue Characteristics
Muscle tone.
A muscle in partial contraction.
A few fibers are contracting at all times. (recruitment)

57. Skeletal Muscle Tissue Characteristics
Thursday 12/4 Page
Muscular Atrophy
Don’t use it and you lose it!
Muscular Hypertrophy
Muscle getting bigger due to work?

58. Cardiac Muscle Tissue Characteristics

59. Cardiac Muscle Tissue Characteristics

60. Smooth Muscle Tissue Characteristics

65. How Skeletal Muscles Produce Movement
Origin
Insertion

66. How Skeletal Muscles Produce Movement
Group actions
Prime mover
Antago
Synergists
fixators

68. Naming Muscles
Direction of Muscle fibers

69. Naming Muscles (cont)
Location

70. Naming Muscles (cont)
Number of origins

71. Naming Muscles (cont)
Shape

72. Naming Muscles (cont)
Origin and insertion

73. Naming Muscles (cont)
Action

74. Naming Muscles (cont)
Size

76. 4 Characteristics of Muscle Tissue
Tortora pages 154
4 Characteristics of Muscle Tissue
Excitability:
Ability of tissue to receive and respond to stimuli.
Contractility:
Ability to shorten and thicken.
Extensibility
Ability of muscle tissue to stretch.
Elasticity
Ability of muscle tissue to return to its original shape after contraction or extension.