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Introduction to Body structure

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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.

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