ANS 331: Introduction to Physiology

I. 	Overview

	Physiology--the study of the functions of living organisms.

		Viral Physiology				

		Bacterial Physiology				

		Plant Physiology

		Animal Physiology 

			--Cellular Physiology
			--Systemic Physiology

		Human Physiology

	Anatomy--the study of the structure of an organism
		The structures, shapes, and organization of the parts of 
		the body are intimately associated with their functions.

	Growth--an increase in mass of structural tissues and organs 
		accompanied by a change in form or composition of the 
		organisms body

	Development--the directive coordination of all diverse processes 
		until maturity is reached

		Involves growth, cellular differentiation, and changes in 
		body shape and form.

II.	Basic Structural Levels

	1. 	Cells--Basic structural and functional unit of life

		Properties:	Contractility

				Conductivity

				Metabolism

				Irritability

				Reproduction

	2.	Tissues--Groups of cells joined together to perform a 
			physiological action

		A.	Derived embryonically from 3 cell layers

			a.	Ectoderm
			b.	Endoderm
			c.	Mesoderm

		B.	Tissues are divided into 4 primary categories

			a.	Epithelial Tissues

				--Cover Body Surface and line body cavities,
					ducts and vessels.

				--Develop from ecto-, meso-, and endoderm

			b.	Muscular Tissues

				--Move skeleton, pump blood, move food 
					through digestive tract, and gametes
					and conceptus through reproductive 
					tracts

				--Develop from mesoderm

			c.	Nervous Tissues

				--Form the brain, spinal chord, and nerves

				--Develop from ectoderm

			d.	Connective Tissues

				--Used for support and the attachment of 
					other tissues

				--Develop from mesoderm



	3.	Organs--Two or more tissues joined together to form more 
				complex physiologic activities.

			e.g. Brain, Heart, Lung, Stomach, Intestine, 
				Kidney, Liver, and Skin.



	4.	Systems--Two or more organs working together to perform 
				specific parts of body functions.

		A.	Integumentary

			a.	Skin
			b.	Hair
			c.	Hoofs

		B.	Skeletal

			a.	Bones

		C.	Muscular

			b.	Skeletal Muscles

		D.	Nervous

			a.	Brain
			b.	Spinal Cord
			c.	Nerves
			d.	Sense Organs

		E.	Endocrine

			a.	Endocrine Glands

				--Pituitary, Gonads, Thyroid, Adrenal, etc.

		F.	Circulatory (Cardiovascular)

			a.	Heart
			b.	Blood & Lymphatic Vessels
			c.	Blood & Lymph

		G.	Respiratory

			a.	Nose
			b.	Trachea
			c.	Lungs

		H.	Digestive

			a.	Mouth
			b.	Esophagus
			c.	Stomach
			d.	Intestines
			e.	Salivary glands
			f.	Pancreas
			g.	Liver (Hepatic)
			h.	Gallbladder

		I. 	Urinary

			a.	Kidneys (Renal)
			b.	Ureters
			c.	Bladder
			d.	Urethra

		J.	Reproductive

			a. 	Male Organs

				--Testes, Accessory Glands, Penis, etc.

			b.	Female Organs

				--Ovaries, Oviducts, Uterus, Vagina, 
					Mammary Glands, etc.

		H. 	Immune System

			a.	Spleen
			b.	Thymus
			b.	Lymph Glands and Nodes
			c.	Circulatory System	

III.  Body Orientation Terminology	

	1.	Directional Terms

		A.	Cranial or Anterior vs. Caudal or Posterior

			a.	Cranial or Anterior

				--Towards the head

			b.	Caudal or Posterior

				--Towards the tail or buttocks



		B.	Rostral

			a.	Towards the tip of the nose



		C.	Dorsal vs. Ventral

			a.	Dorsal--Towards the back

			b.	Ventral--Towards the belly



		D.	Medial vs. Lateral

			a.	Medial--Towards the median plane 
					(center line of body)

			b.	Lateral--Away from median plane

		E.	Deep or Internal 

			vs. Superficial or External

			a.	Deep or Internal--Towards the center 
					of the body or body part

			b.	Superficial or External--Towards the surface 
					of the body or body part

		F.	Proximal vs. Distal

			a.	Proximal--Towards the body 
					or body part

			b.	Distal--Away from the body 
					or body part

		G.	Visceral vs. Parietal

			a.	Visceral--Towards an organ

			b.	Parietal--Away from an organ



	2.	Anatomical Planes of Reference

		A.	Sagittal Plane

			a.	A plane that runs the length of the body 
				and divides left and right parts.

			b.	Not necessarily equal halves

		B.	Median Plane

			a.	A sagittal plane that runs down the center
				of the body and divides into equal left 
				and right halves

			b.	Also called midsagittal

		C.	Transverse Plane

			a.	A plane across the body which divides into cranial 
				and caudal parts

			b.	Not necessarily equal



		D.	Dorsal Plane

			a.	A plane at right angles of the sagittal 
				and transverse planes

			b.	Divides body into dorsal and ventral parts

			c.	Not necessarily equal

	3.	Body Cavities

		A.	Dorsal Body Cavity

			a.	Cranial body cavity

				i.	Formed by skull

				ii. Contain brain

			b.	Spinal body cavity

				i.	Formed by vertebrae of spine

				ii.	Also called spinal canal

		B.	Ventral Body Cavity

			a.	Thorax or Thoracic cavity

				i.	Chest area

				ii.	Cranial to diaphragm muscle

				iii.	Lined by membranes called pleura

					–Visceral and Parietal layers

			b.	Abdominal or Peritoneal cavity

				i.	Caudal to diaphragm muscle

				ii.	Lined by membrane called peritoneum

					–Visceral and Parietal layers


III.	Homeostasis



	1.	A state of body equilibrium

		A.	How the body organs function together to maintain 
			a stable internal environment for the general 
			well-being of the body

		B.	Chemical and Physical Balance

	2.	Homeostatic mechanisms

		A.	Sensing and Compensating

			a.	Nervous system

			b.	Endocrine system

		B.	Negative Feedback

			a.	Primary mechanism maintaining homeostasis

				--Change in opposite direction of initial change

			b.	Components

				i. 	Controlled system

				ii.	Set Point

				iii.	Receptor

				iv.	Processing center		



		C.	Positive Feedback

			a.	Change in same direction of initial change

			b.	Not used to maintain homeostasis			

			c.	Important in certain physiological circumstances

				--Childbirth, "fight or flight" responses, 

					Ovulation Signal, etc.