How Animals Move Chapter 20 Animal Movement The

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How Animals Move Chapter 20

How Animals Move Chapter 20

Animal Movement: The Skeletal System ● Types of Skeletons: a. Hydrostatic ■ Soft-bodied invertebrates

Animal Movement: The Skeletal System ● Types of Skeletons: a. Hydrostatic ■ Soft-bodied invertebrates ■ internal fluid-filled chamber that muscles exert force against internal fluid-filled chamber(s)

Animal Movement: The Skeletal System ● Types of Skeletons: b. Exoskeleton ■ Arthropods (insects,

Animal Movement: The Skeletal System ● Types of Skeletons: b. Exoskeleton ■ Arthropods (insects, arachnids, crustaceans) ■ Hard external parts that receive the force of muscle contraction

Animal Movement: The Skeletal System ● Types of Skeletons: c. Endoskeleton ■ Echinoderms and

Animal Movement: The Skeletal System ● Types of Skeletons: c. Endoskeleton ■ Echinoderms and vertebrates ■ Internal framework of hardened elements that muscles attach to and contract against

The Human Skeleton ● Flattened cranial bones surround and protect the brain

The Human Skeleton ● Flattened cranial bones surround and protect the brain

The Human Skeleton ● Vertebral column (backbone) ● 23 individual vertebrae separated by intervertebral

The Human Skeleton ● Vertebral column (backbone) ● 23 individual vertebrae separated by intervertebral discs ● Protects the spinal cord, which connects with the brain at an opening at the base of the skull

The Human Skeleton ● Thoracic cage has 12 pair of ribs ● Breastbone (sternum)

The Human Skeleton ● Thoracic cage has 12 pair of ribs ● Breastbone (sternum) ● Together, both protect the heart and lungs

The Human Skeleton ● Pectoral girdle made of clavicle (collarbone) and scapula (shoulder blade).

The Human Skeleton ● Pectoral girdle made of clavicle (collarbone) and scapula (shoulder blade). ● Attaches arm to trunk of body

The Human Skeleton ● Upper arm (humerus) ● Lower arm ○ Radius (thumb side)

The Human Skeleton ● Upper arm (humerus) ● Lower arm ○ Radius (thumb side) ○ Ulna (pinky side)

The Human Skeleton ● Pelvic girdle protects organs and supports weight of the upper

The Human Skeleton ● Pelvic girdle protects organs and supports weight of the upper body. ● Bones of lower body in general are much larger than upper body because they support your body’s weight.

The Human Skeleton ● Leg ○ Thigh = femur= largest bone in the body

The Human Skeleton ● Leg ○ Thigh = femur= largest bone in the body ○ Lower leg = tibia (shin bone-larger) and fibula (smaller) ○ Patella (kneecap)

Bone Structure and Function ● Bones are organs. ● Many functions: ○ Movement ○

Bone Structure and Function ● Bones are organs. ● Many functions: ○ Movement ○ Protection of organs ○ Blood cell formation ○ Reservoir for calcium

Bone Structure and Function ● Two types of bone tissue: ○ Compact bone ■

Bone Structure and Function ● Two types of bone tissue: ○ Compact bone ■ Makes up the outer weightbearing part of long bones like the femur ■ Consists of many thin concentric layers of matrix surrounding a central canal where blood vessels and nerve fibers run through the bone

Bone Structure and Function ● Two types of bone tissue: ○ Spongy bone ■

Bone Structure and Function ● Two types of bone tissue: ○ Spongy bone ■ Makes up the middle of the shaft and the ends of a long bone ■ Has many spaces that contain red marrow (forms blood cells) and yellow marrow (made up mostly of fat cells)

Bone Structure and Function ● Ongoing mineral deposits and removals from bone help to

Bone Structure and Function ● Ongoing mineral deposits and removals from bone help to maintain the correct level of calcium in the blood, which is very important to nerve cell function and muscle contraction

Osteoporosis ● As people age, the rate of bone buildup slows down and bone

Osteoporosis ● As people age, the rate of bone buildup slows down and bone break down speeds up, resulting in a decrease in bone density. ● Osteoporosis results when bone loss greatly outpaces bone formation. ● Osteoporosis most commonly occurs in postmenopausal women because they lack the sex hormones that encourage bone deposition. However, about 20% of osteoporosis cases occur in men.

Osteoporosis ● Risk factors: ○ Low intake of calcium ○ Smoking ○ Drinking ○

Osteoporosis ● Risk factors: ○ Low intake of calcium ○ Smoking ○ Drinking ○ Lack of exercise ○ Too many soft drinks ○ Postmenopausal female ○ Low body weight ○ Family history

Skeletal Joints ● Fibrous -hold cranial bones together-immovable ● Cartilaginous- connect ribs to sternum-little

Skeletal Joints ● Fibrous -hold cranial bones together-immovable ● Cartilaginous- connect ribs to sternum-little movement ● Synovial-most common type-freely movable ○ Ligaments- connective tissue that connects bone to bone

Bone and Skeletal Muscle Interaction ● Tendons-connective tissue that connects muscle to bone ●

Bone and Skeletal Muscle Interaction ● Tendons-connective tissue that connects muscle to bone ● When a muscle contracts, it transmits force to the bone to which it is attached and makes it move. ● Muscle can only PULL on bones; they cannot push. ● Therefore, muscles usually work in opposition to one another called antagonistic pairs)

Bone and Skeletal Muscle Interaction ● For example, the triceps brachii flexes the forearm,

Bone and Skeletal Muscle Interaction ● For example, the triceps brachii flexes the forearm, while the biceps brachii extends the forearm.

Bone and Skeletal Muscle Interaction

Bone and Skeletal Muscle Interaction

Skeletal Muscle Structure and Function ● Each skeletal muscle consists of bundles of muscle

Skeletal Muscle Structure and Function ● Each skeletal muscle consists of bundles of muscle cells (fibers) held together by connective tissue. ● Each muscle fiber consists of many myofibrils.

Skeletal Muscle Structure and Function ● Sarcomere: basic unit of muscle contraction ● Made

Skeletal Muscle Structure and Function ● Sarcomere: basic unit of muscle contraction ● Made up mainly of myosin (thick, dark filaments) and actin (thick, light filaments), which are responsible for the striations of skeletal muscle.

How a Muscle Contracts ● Sliding Filament Model ● Actin and Myosin filaments do

How a Muscle Contracts ● Sliding Filament Model ● Actin and Myosin filaments do NOT shorten ● Heads on the myosin filaments (called cross bridges)attach to and slide the actin filaments past the myosin, causing the sarcomere to shorten (= contraction)

How a Muscle Contracts ● Myosin heads release from actin when ATP binds to

How a Muscle Contracts ● Myosin heads release from actin when ATP binds to them. ● This is why dead people stiffen (called rigor mortis). ● Dead = no more ATP = myosin heads can’t release= no relaxation = stiff

How a Muscle Contracts

How a Muscle Contracts

Whole Muscle Properties ● Each motor neuron and the muscle fibers it stimulates is

Whole Muscle Properties ● Each motor neuron and the muscle fibers it stimulates is called a motor unit. ● Small motor units= fine movement= more control (fingers) ● Large motor units = less fine movement but more force (tension)= arm (biceps)

Whole Muscle Properties ● Muscle fatigue ○ Decrease in muscle capacity to generate force

Whole Muscle Properties ● Muscle fatigue ○ Decrease in muscle capacity to generate force ○ Powerful contractions done very quickly do anaerobic respiration (without oxygen)= glycolysis only ○ This results in buildup of lactic acid=cramps