1. & D.4 Cardiac Muscle Cells (p 685)
11.2 Movement
& D.4 Cardiac Muscle Cells (p 685)

2. Movement KINESIOLOGY: The study of movement of the human body
What happens when somebody moves?
Your brain sends an impulse (an action potential) through a nerve to a muscle to tell it to contract.
Muscles are connected to bones by tendons.
When a muscle contracts, it will move the bone.

3. Bones Rigid structures for anchoring muscles
They contain several different tissues and therefore are organs.
Functions:
provide a hard framework to support the body
Protect vulnerable softer tissues and organs (ex: the heart and lungs are protected by the ribcage)
Act as levers so that body movement can occur
Form blood cells in bone marrow
Storage of minerals (ex: calcium and phosphorus)

4. The Human Skeleton Adult humans have 206 bones (newborns have ~270
Remember why?)
26 bones in your vertebral column
12 pairs of ribs
Teeth are not considered to be bones

5. Of the 206 bones in the body, 106 of them are found in your hands and feet

6. http://www. pennmedicine. org/encyclopedia/em_DisplayAnimation. aspx

7. Exoskeletons
Some animals do not have bones but have exoskeletons that provide a similar function.
Exoskeletons are external skeletons that surround and protect most of the body surface of crustaceans, insects, and spiders

8. Did you know? As an insect grows, its exoskeleton breaks open
The enlarged insect will emerge leaving the old exoskeleton behind.
It will take some time for a new exoskeleton to fully develop and harden.
During this time, the insects soft exoskeleton will make it vulnerable to predators and environmental factors.

9. Levers
Bones and exoskeletons facilitate movement by anchoring muscles and acting as a lever.
Muscles are attached to the outside of bones and the inside of exoskeletons
A lever is a rigid rod (the bone) that turns about a pivot (usually a joint).
Levers change the size and direction of forces.

10. Lever Components Lever arm Effort force Fulcrum (pivot point) Load
In our bodies, it’s the bone
Effort force
This is where the force is exerted, provided by muscles
Fulcrum (pivot point)
Load
The body part that is moved (as a result of the Resultant Force)
Provides Resistant Force

11. First Class Lever The fulcrum is in between the effort and the load
Like a see-saw.
When effort force is applied, the resultant force causes the load to move up.
Ex: Nodding Your Head

12. First Class Lever- Nodding
The pivot/fulcrum is where the skull meets the top of the spine
The neck muscles contract to provide the effort force to move the spine down and the resultant force to move the chin up.
When the neck muscles relax, the chin move down

14. Second-Class Lever
The resultant force in between the pivot and the load
Like a wheelbarrow.
There is a mechanical advantage because less effort force is required
Ex: Standing on your tip toes

15. Second Class Lever – Tippy Toes
The pivot is at the toe joints
The foot is the lever arm
When the calf muscles contract, it provides the effort force required to lift the load (the body)

17. Third Class Levers
The effort force is in between the pivot and the load
No mechanical advantage, more effort force is required to lift the load.
Ex: Bending your arm

18. Third Class Lever – Bending Arm
The pivot is at the elbow joint
The muscles in the upper arm (bicep) provide the effort force require to bend the forearm

22. Muscles and Tendons Skeletal Muscles are attached to bones
Tendons are what attach muscles to bones
Tendons are cords of dense connective tissue
Muscles provide the force necessary for movement by shortening the length of their fibres.
They work in antagonistic pairs to achieve movement
When one muscle contracts, the other relaxes

23. Antagonistic Muscle Action
When the biceps contract, the tendon pulls on the bone pulling the lower arm up. The triceps are relaxed
When the triceps contract, it causes the bones to straighten. The biceps are relaxed.
Biceps = muscles at front of upper arm
Triceps = muscles at the back of the upper arm

24. Remember Ventilation?
The process of ventilation required the movement of antagonistic muscle pairs
INHALATION: The external intercostal muscles CONTRACT; the internal intercostal muscles RELAX to ex
EXHALATION: The internal intercostal muscle CONTRACT; the external intercostal muscles RELAX

26. Antagonists Muscles in Insect Legs
femur
tibia
tarsus

27. Antagonist Muscles in Insects Legs
When the grasshopper prepares to jump:
FLEXING:
The flexor muscles will contract bringing the tibia and tarsus in a “Z” position.
The extensor muscles are relaxed.
EXTENDING:
The extensor muscles contract to extend the tibia and produce a powerful propelling force.

28. JOINT Also called an articulation or arthrosis
The point where 2 or more bones contact one another
Joints cause mobility and hold the body together
Most joints include:
Bones
Ligaments
Muscles
Tendons
nerves

29. Annotate Human Elbow Joint p478
Tendon
Spongy Bone
Ligament

31. Elbow Joint Spongy Bone Cartilage
the end of each bone is made of spongy bone
It is light but strong (provides strength without too much mass)
Cartilage
The covering at the end of a bone
It has a smooth surface which provides easy movement, preventing friction
Absorbs shocks

32. Elbow Joint Joint Capsule Synovial Fluid Synovial Membrane
Seals the space between the bones at a joint
Helps prevent dislocation
Synovial Fluid
Fluid at joint capsule
Acts as a lubricant for the joint to prevent friction.
Contains the required food and oxygen to maintain cartilage
Synovial Membrane
Secretes synovial fluid and keeps it within the joint

33. Elbow Joint Ligaments Biceps Triceps
Tough tissues that attach bones to bones
Keeps the bones together in correct relative position
Biceps
Muscles in upper arm that will bend the arm
Triceps
Muscles in upper arm that will straighten the arm

34. Elbow Joint Humerus Radius Ulna
Upper arm bone attached to the biceps and triceps
Radius
Lower arm bone attached to the biceps (via a tendon)
Ulna
Lower arm bone attached to the triceps (via a ligament)

35. Elbow Joint
The elbow joint is called a synovial joint because of the presence of the synovial cavity.
There is a rich supply of blood to joints.
If blood vessels supplying the joint gets damaged and there is local bleeding, it may result in swelling of the area

36. Other Joints Synovial Joints have a lubricating synovial cavity
Most common
Provides lots of movement
Cartilaginous Joints
Joins bones with cartilage
Ex: spinal column
Fibrous Joints
Joins bones with connective tissue (collagen)
Immobile
Ex: Skull Bones

37. “Joint Terms”
Flex and Extend = ex: movement that moves your leg back and forth (like a pendulum)
Flexion = decrease the angle between the connecting bones
Extension = increase the angle between the connection bones
Abduction and adduction = moving your leg sideways (away from the center of the body)
Abduction = bones moves away from body’s midline
Adduction = bones move toward body’s midline
Rotation = bone moves along its own longitudinal axis

39. Hinge Joints
Provides an opening-and-closing type of movement like the action of a door
This movement is in one direction – flex and extend
Ex: the elbow joint, the knee joint

41. Ball-and-Socket Joints
Allows for movement in several directions
Flex and extend
Abduction and adduction
Rotational movement
Ex: hip joint
the head of the femur is ball shape and fits into a cup like depression of the hip bone

43. Joints and Movement
The structure of the joint (including the joint capsule and ligaments) determine the movements that are possible.
KNEE JOINT
HIP JOINT
Synovial Joint
Involved in movement of the leg and required for walking
Involved in the movement of the leg and required for walking
Hinge Joint
Ball and Socket
Possible Motions:
Flex and Extend
Small amount of rotation
Abduction and Adduction
Rotation
Movement in one direction
Movement in many directions (multiaxial)

44. Muscles Human body has 3 types of muscles
Cardiac muscle (muscle exclusive to the heart)
Smooth muscle (also known as non-striated muscle)
Muscle that makes up organs such as the stomach
Skeletal Muscle (also known as striated muscle)
Muscle associated with bones and therefore involved in movement

45. Striated Muscle Fibres
Like all other body tissues, muscles are made up of cells.
Muscle cells are called muscle fibres
They are elongated in shape
The arrangement of proteins within them create a banded appearance or stripes under a microscope which is why is it called striated muscle

50. Parts of a Muscle Fibre
Each muscle cell was originally many cells fused together, which is why a muscle cell has many nuclei.
Sarcolemma: membrane surrounding the muscle cell
Sarcoplasm: the cytoplasm of the muscle cell
Within the sarcoplasm there are multiple mitochondria for ATP production (because muscle contractions require a lot of energy)

51. Parts of a Muscle Fibre Sarcoplasmic Reticulum:
membrane found within the sarcoplasm (similar to the ER)
Stores and releases calcium ions into the sarcoplasm which will trigger a muscle contraction

53. Parts of a Muscle Fibre Myofibrils:
Thin fibres inside the muscle cell
There are many myofibrils in a muscle fibre
Create the striated (striped) pattern of light and dark skeletal muscles
Contain 2 types of myofilaments: myosin and actin which are made of proteins
Each myofibril is made up of contractile sarcomeres
Sarcomere: a functional unit of the muscle (a segment of a myofibril)

56. Sarcomere

57. Sarcomere
Intermediate Section Light section Dark Section Dark Section Light Section

58. Sarcomere
Z line
Z line

59. Sarcomere
A sarcomere is
found between two
Z-lines

60. Sarcomere Thin actin filaments form the I band
They are attached to the Z line
Thick myosin filaments are found in the A band
In the dark regions, myosin and actin overlap
In the gray H zone, only myosin is present

63. Myofilaments - MYOSIN
Myosin filaments contain several myosin strands bundled together (that’s why they’re the thick filament!)
Each myosin strand has a “hook” or a “head” that binds to actin.
The ends without “heads” are the “tails” and they are found within the H zone

64. Myofilaments -ACTIN
Actin filaments contain strands of actin and 2 proteins: TROPOMYOSIN and TROPONIN
2 strands of tropomyosin wind around the actin filament covering the binding site for the myosin hooks
This prevents the muscle from contracting

65. Actin Filament

67. Sliding Filament Theory
Actin and myosin slide over each other to make the muscle shorter (actin and myosin stay the same size!)
Little “hooks” on the myosin filaments attach to the actin and pull them closer to the center of the sarcomere
This shortens the sarcomere and the overall length of the muscle fibre  muscle contraction
Myosin then releases the actin and repeats the hooking and pulling action further down the actin.
This is done with ATP energy (from the mitochondria!)
As the filaments slide over each other, the H bands disappears and the I band shortens

70. Which one is relaxed? Which one is contracted?

71. http://highered. mcgraw-hill

72. Muscle Contraction
When you want to start a muscle contraction, a nerve impulse arrives at the muscle
The action potential causes the sarcoplasmic reticulum to release calcium ions into the sarcoplasm
The Ca2+ attach to troponin (which is attached to tropomyosin) causing tropomyosin to uncover the binding sites for the myosin hooks.

73. Actin Filament

74. Muscle Contraction
The myosin hooks will have an ATP molecule bonded to it already. The ATP will hydrolyse into ADP and Pi (but will still be attached to the myosin hook)
The myosin hooks can now bind to the binding sites on the actin filament, forming cross-bridges.

77. Muscle Contraction
The ADP and Pi dissociate from the cross-bridge and the myosin hooks bend, pulling the actin filaments toward the M line. This is called the power stroke. It causes the myofilaments to slide over each thus the muscle fibre contracts
A new ATP molecule will attach to the myosin hook and the myosin will detach from the binding site.
The process may repeat with the hooks attaching to binding sites further down the actin filament.

78. http://highered. mcgraw-hill

81. Muscle Relaxation
Contraction cycles will continue as long as ATP is available and Ca2+ is present in the sarcoplasm
When the nerve impulse stops, Ca2+ move back into the vesicle of the sarcoplasmic reticulum by active transport
This causes the binding sites on the actin to be covered again (so myosin cannot bind)
The muscle will relax.

83. Cardiac Muscle Cells p685
The structure of cardiac muscle cells allows for propagation of stimuli through the heart wall.
Remember, cardiac muscle tissue is unique.
It is also striated in appearance, and the arrangement of myofilaments is similar to skeletal muscle.

84. Cardiac Muscle Cells How do they differ from skeletal muscle fibres?
Cardiac muscle cells are shorter and wider.
They have only 1 nucleus per cell.
Cardiac muscle contraction is not under voluntary control (myogenic!)
Many cardiac muscle cells contract even in the absence of stimulation by nerves for the entire life of the organism!

86. Cardiac Muscle Cells The cells are Y-shaped.
There is a specialized junction called an intercalated disc where the end of one cell meets the end of another cell
The intercalated disc consists of a double membrane containing gap junctions which are channels that provide a connection between the cytoplasm of adjacent cells.
This allows for the rapid movement of ions from one cardiac cell to the next, with low electrical resistance.

87. Cardiac Muscle Cells
So, their Y-shape and gap junctions allows them to be electrically connected
This means a wave of depolarization can easily pass form one cell to a network of other cells leading to synchronization of muscle contraction allowing for both atria or both ventricles to contract simultaneously as if it was one large cell.