Download Chapter 45

Chapter 45

Skeletal, Muscular and Integumentary Systems
45-1
* Human Body Plan
Four types of Human Tissue
1. Muscle
2. Nervous
3. Epithelial
4. Connective
Muscle Tissue
*Can contract and relax.
a) Skeletal muscle- voluntary, usually moves bones
b) Smooth muscle- involuntary, breathing, digestion ….
c) Cardiac muscle – involuntary, in the heart
Nervous Tissue
*Cells that receive and send messages by electrical impulse
*Neurons- nerve cells
*Neurons are in nervous tissue and sensory organs. They coordinate all activities.
Epithelial Tissue
*Layers of cells that cover or line internal and external surfaces.
*Skin, but also in blood vessels, respiratory system, digestive system,….
*This forms a protective barrier
Connective Tissue
*Connects, supports, protects
*Includes cartilage, bone, tendons, ligaments, fat, blood and lymph.
Matrix- intercellular substance- can be solid (bone), semisolid (fat) or liquid (blood)
Organ Systems- Page 907
1. Skeletal
7. Digestive
2. Muscular
8. Excretory
3. Integumentary
9. Nervous
4. Circulatory
10. Endocrine
5. Respiratory
11. Reproductive
6. Immune
The systems work together, organs may overlap systems.
Ex. Respiratory and Circulatory Systems
1
Body Cavities
a) Cranial –brain
b) Spinal
c) Thoracic –above diaphragm
d) Abdominal-below diaphragm
45-2
*Skeletal System
206 Bones
*Axial- skull, ribs, spine, sternum
*Appendicular- arms, legs, scapula, clavicle, pelvis
Bones are used for
*Support
*Movement
*Protection
*Mineral Storage
*Production of blood cells
Bone Structure
Bones contain living cells
Periosteum
*Thick membrane around the
bone
*contains blood vessels and
nerves
Compact Bone
*Provides strength
*has blood vessels running
through Haversion Canals
Osteocytes- the living bone cells
embedded in the matrix.
Spongy Bone
*in the center of the bone and at the ends of the bone
*it makes bones light and strong
*acts as a “cushion”
Bone Marrow
Red- produces RBC and some WBC
Yellow- contains fat, can convert to red bone marrow
2
Ossification
*Cartilage becomes hard due to mineral deposits
*starts at about the 3rd fetal month and continues to adulthood.
*you must have proper minerals!
Bone Growth
*Elongation takes place at the Epiphyseal Plates (the ends of the bones)—older cells are
in the middle of the bone, and newer cells are at the end.
Joints
*Places where bones meet
a) fixed- skull
b) semi-movable- vertebrae, ribs..
c) movable- know types and locations
Ligaments
*tough connective tissue
*they hold bones together
Joints contain Synovial Fluid and cartilage to reduce friction
Skeletal Problems
Rheumatoid arthritis-the immune system attacks the joint tissue
Ostoearthritis-Cartilage wears away, bones rub
Osteoporosis-loss of bone minerals- bones become brittle and weak.
45-3
*Muscular System
Skeletal or Striated Muscles
*Made of Muscle Fibers
a) contain many nuclei
b) have striations—light and dark stripes
Muscle Structure—
Made of 100’s to 1000’s of muscle fibers
*covered by connective tissue
*controlled by nerves
Myofibrils (thread-like structure of a muscle fiber)
Made of two types of protein filaments
a) Myosin- thick fibers with “heads”
b) Actin- thin fibers
Z-Line- where actin fibers are attached
Sarcomere- area from one Z-line to the next
3
Muscle Contractions
*When a muscle contracts, the myosin “heads” pull the actin in
* the muscle shortens
*Muscle contractions require ATP—it is used to detach the myosin “heads” from the
actin.
All or None
*the fiber is either contracted or relaxed
*heavier objects require more muscle fibers
Tendons—Page 917
*Attach muscle to bone
Origin-stationary point where muscle attaches to bone
Insertion- where muscle attaches to moving bone.
Opposing Pairs
Muscles work in pairs—one contracts and one relaxes
Flexor-muscle that bends a joint ex. biceps
Extensor- muscle that straightens a joint ex. Triceps
Muscle Fatigue
Muscle has used up ATP
Continuous contractions—muscle cramps
Oxygen Debt
There is not enough oxygen to break down ATP
Build up of lactic acid
45-4
Integumentary System
Skin
1) Epidermis-outer layer
2) Dermis-inner layer
Epidermis
*Sheets of mostly dead cells
*Cells contain Keratin-a protein, helps make skin almost waterproof
*Constantly being replaced
Melanin
*Brown pigment in the skin.
*Amount of melanin depends on
1) heredity
2) exposure to UV
4
Dermis
*Living layer
a) sensory neurons
b) blood vessels
c) muscles
d) hair follicles
e) exocrine glands
Subcutaneous Fat
*a layer of fat under the
skin
*energy store
*insulation
Nails and Hair
Made of keratin—cells are dead
The follicle—root of the hair, is alive.
Sweat Glands
*remove waste products
*regulates body temperature
Sebaceous Glands
Produce Sebum (oil)
Softens skin and hair
Bacteria in glands cause acne.
-
5