Web Site

1. Web Site http://www.oswego.edu/~balko/

2. Tissues & Organs of Humans Chapter 4

3. Themes of organism function • 1. Structure and function are correlated • 2. Life has the ability to adjust to its environment physiologically & ultimately as adaptation

4. 4 basic Human Tissue Types • Epithelia • Connective • Muscle • nervous

5. 1. Epithelia • sheets of tightly packed epithelial cells • covers outside of the body (skin or epidermis) & lines organs & cavities inside body (endothelium) • classified by numbers of layers & shape of cells • function to • a) absorb nutrients • b) lubricate a surface • c) secrete chemicals - glands.

7. Glands • Exocrine glands: secretion into ducts to exterior of body • Endocrine glands: secretion into the blood to carry chemical messages throughout the body

8. 2. Connective Tissue • Not tightly packed, cells are scattered throughout an extracellular matrix • matrix may be liquid, solid, or jelly-like • Functions: bind & support other tissues • Main component matrix fibrous protein collagen. • Two possible cell types of matrix • a) fibroblasts - secretes collagen • b) macrophages - amoeboid cells that roam matrix eating bacteria and dead cells • Tissue examples: cartilage, bone, & blood

9. Loose Connective Tissue • function - bind epithelia to underlying tissues, hold organs in place, or transport of materials  fibers are loosely woven • Examples: • Collagenous fibers - do not tear easily; keeps flesh on bone • Elastic fibers (elastin) - resist stretching, rubbery • Adipose tissue - contains cells which store fat, bound in a fibrous matrix; cells shrink or swell • Blood - matrix is liquid (plasma), transport

12. Fibrous Connective Tissue • dense, tightly woven, in parallel bundles • Types Fibrous Connective Tissue: • a. Tendons - connect muscle to bone • b. Ligaments - connect bone to bone at joints • c. Cartilage - flexible; nose, ears, between vertebrae • d. Bone - hardest connective

14. Functions of Bone • supports the body (against gravity) • attachment point for muscles • protects organs e.g. ribcage, skull • some bones produce red blood cells • acts as a reservoir for calcium

15. 3. Muscle Tissue • Skeletal • Cardiac • smooth

16. Skeletal (striated) muscle • attaches to bones • moves the skeleton • voluntary - under conscious nervous control • striated (striped) appearance

17. Cardiac muscle or heart muscle • Striated w/ intercalated disks • cells only contain a single nucleus • under control of autonomic nervous system (unconscious control)

18. Smooth muscle • lacks the striations of skeletal muscle • involuntary muscle, under autonomic control • visceral muscle - operates the gut; found in iris of eye, base of hairs, uterus

20. 4. Nerve Tissue • composed of neuron cells • receives information from environment (stimulus) through sensory receptors • information sent as electrical & chemical signals to brain • Brain interprets signals and produces proper response • signals are then sent from brain to effectors where response is initiated

22. Homeostasis ("same state") • maintenance of physiological conditions required to support the life of the organism

23. Homeostatic response • serves to keep physiological conditions within a certain acceptable range to support life. • generally automatic, brought on by feedback loops

24. Feedback Loops • negative or positive (more on this later). • continuous, automatic adjustments, collectively called regulation. • regulation maintained by the nervous system & endocrine system.

25. Nervous System Control • simple rapid & automatic reflex reaction causing a regulatory response to a potential threat. (e.g. knee jerk) • interaction between nervous system & musculoskeletal system

26. Endocrine System Control • acts more slowly than nervous system • changes in levels of nutrients in the bloodstream trigger the release of hormones • hormones effect target tissues or organs