1. Introduction to Body structure
Chapter 37
Introduction to Body structure

2. Levels/structure of organization
Body Organization
Levels/structure of organization
Cells, tissues, Organs and Organ systems
We did cells already
Tissues:
Epithelial: lines most body surfaces, also typically flat and thin
Nervous: makes up the nervous system, nerve cells and supporting tissue
Connective: support, protect, and insulate the body. Example bone.
Muscle: three types, enable movement.
Skeletal: voluntary, moves bones in the trunk and limbs
Smooth: involuntary, line walls of blood vessels, and organs
Cardiac: involuntary, found in the heart.

3. Stem Cells: embryonic stem cells are immortal, they divide indefinitely. They are not specialized, meaning they can become any cell. Stem cell research is very controversial.
Organ systems: two or more types of tissues working together to perform a certain function.
Page 848, major organ systems of the body. You should know the basics for this test, but we will be going into detail in all of them over the next couple of weeks.
Human body cavities: consists of 4 fluid filled spaces where organs are found.
Cranial cavity
Spinal cavity
Thoracic cavity
Abdominal cavity

4. Endothermy: We are endotherms, maintain a fairly constant internal temperature: approx. 37 degrees C.
Maintained by the food we eat, large amount of energy consumed by our body is to regulate this temp.
Maintained via the flow of blood through the body.
Skeletal system (yes you will need to know the bones, and there is a bones test).
keeps your body from being floppy
Provides protection for internal organs
Human skeleton has 206 individual bones.
80 form the axial skeleton (bones of the skull, spine, ribs, and sternum)
126 form the appendicular skeleton (arms, legs, pelvis, and shoulder)

6. Axial Skeleton
Most complex is the skull (29 bones in the skull, 8 form cranium, 14 facial, 6 middle ear, and a single bone that supports the base of the tongue).
26 vertebrae
12 pairs of ribs.
Appendicular skeleton
Everything else 
Bone structure
Hard outer covering of compact bone (dense connective tissue) surrounding a porous inner core of spongy bone.
Bone marrow, Red: begins the production of all blood cells and platelets; yellow mostly fat, stores energy.
periosteum: protective outer membrane that helps protect the bone, contains many blood vessels that supply nutrients to the bone.
Bone Growth
Haversian canals: hollow narrow channels, where new bone growth occurs.
Osteocytes: bone cells, supplied by nutrients via haversian canals.
Osteoporosis: porous bone, bones become brittle and weak.

7. Joints: where two bones meet
Ligaments: hold two bones together
Three main types of joints immovable: little to no movement, base of cranium
Slightly movable: limited amount of movement, vertebrae
Freely movable: permit movement, several types. (you will need to know examples of each) See page 854
Ball and socket: , all types, shoulders and hips
Pivot: rotation, top of spine
Hinge: bending and straightening, elbows, knuckles
Gliding: sliding motion, wrists and ankles
Saddle: rotation, base of thumb

8. Muscular System
Precisely timed and controlled contractions of many skeletal muscles.
Muscles are attached to bones via tendons.
Origin, part that remains stationary in movement. The muscle pulls against the origin
insertion, the bone that moves when muscle contracts. The muscle pulls the insertion towards the origin.
Have opposing pairs (usually), flexor (causes joint to bend) and extensor (causes joint to straighten).
NOT DOING MUSCLE STRUCTURE, CONTRACTIONS, OR MYOSIN AND ACTIN INTERATION. (pages )

9. Actin and Myosin: Protein filaments, enable muscles to contract
Myofibrils: small cylindrical structures in muscle fibers (alternate light and dark bands)
Z line: (found in the light bands) anchors actin filaments
Sarcomeres: area between the 2 z lines.

10. Skin, Hair, and Nails (integumentary system) Skin
About 15 % of your total body weight
Largest organ of the body
A lot of specialized structures
Two primary layers
1. Epidermis: outermost layer, about as thick as a piece of paper, made up of epithelial cells.
When you look in a mirror, you are looking at dead skin cells, made up of Keratin.
Continuously shed and replaced
Melanin: responsible for skin pigment.
2. Dermis: functional layer of skin, just beneath the epidermis. Contains the nerve cells, blood vessels, hari follicles etc.
No to pages 863 and 864 as well.