BME 5100 

CHAPTER 1: HUMAN PHYSIOLOGY

VIEW OF LIFE:

MECHANIST - ALL PHENOMENA CAN BE DESCRIBED IN TERMS OF PHYSICAL AND CHEMICAL LAWS.

VITALIST - SOME VITAL FORCE BEYOND PHYSICS AND CHEMISTRY IS REQUIRED TO EXPLAIN LIFE.

BEFORE DISCUSSING PHYSIOLOGY WE WILL REVIEW SOME BASICS OF CELL BIOLOGY AND BIOCHEMISTRY (CHAPTER 1-7).

CELLS:

THE SIMPLEST STRUCTURAL UNIT CAPABLE OF SUSTAINING LIFE.

A CELL IS ABLE TO:

EXCHANGE MATERIALS WITH ENVIRONMENT

OBTAIN ENERGY FOR ORGANIC NUTRIENTS

SYNTHESIZE COMPLEX MOLECULES

REPLICATE THEMSELVES

CELL DIFFERENTIATION: AS CELLS MULTIPLY THEY BECOME SPECIALIZED TO PERFORM CERTAIN FUNCTIONS.

IE, MUSCLE CELLS, NERVE CELLS

FOUR CATEGORIES OF CELLS:

1. MUSCLE CELLS

2. NERVE CELLS

3. EPITHELIAL CELLS

4. CONNECTIVE TISSUE CELLS

TYPES OF CELLS:

MUSCLE CELLS - SPECIALIZED TO GENERATE MECHANICAL FORCES THAT PRODUCE FORCE AND MOVEMENT.

NERVE CELLS - INITIATE AND CONDUCT ELECTRIC SIGNALS.

EPITHELIAL CELLS - SPECIALIZED FOR SECRETION AND ABSORPTION OF IONS AND MOLECULES. ALSO SERVE TO FORM BOUNDARIES BETWEEN ORGANS.

CONNECTIVE TISSUE CELLS - CONNECT, ANCHOR AND SUPPORT TISSUES IN THE BODY. THEIR EXTRACELLULAR MATRIX OFTEN CONTAINS FIBERS EMBEDDED IN GROUND SUBSTANCE. THE FIBERS INCLUDE COLLAGEN, ELASTIN AND RETICULAR FIBERS.

TISSUES: AGGREGATION OF SIMILAR CELLS THAT PERFORM SAME FUNCTION. IE NERVE TISSUE, MUSCLE TISSUE

TISSUES - SAME FOUR TYPES: MUSCLE, NERVE EPITHELIAL, CONNECTIVE

ORGANS - THE FOUR TYPES OF TISSUES ARE ARRANGED IN VARIOUS PATTERNS TO FORM ORGANS. (IE. HEART, KIDNEY)

ORGAN SYSTEM - A COLLECTION OF ORGANS THAT TOGETHER PERFORM AN OVERALL FUNCTION. 10 ORGAN SYSTEMS - TABLE 1-1.

THE ORGAN SYSTEM MAINTAINS AN INTERNAL ENVIRONMENT SURROUNDING EACH CELL SO THAT THE CELL CAN SURVIVE AND FUNCTION. THIS ENVIRONMENT IS THE EXTRACELLULAR FLUID.

THE MAINTENANCE OF A RELATIVELY CONSTANT INTERNAL ENVIRONMENT IS CALLED HOMEOSTASIS.

BODY FLUID COMPARTMENTS:

TOTAL BODY WATER (TBW) - 60% OF BODY WEIGHT

INTRACELLULAR FLUID - 2/3 OF TBW

EXTRACELLULAR FLUID - 1/3 OF TBW

INTERSTITIAL FLUID - 80% OF ECF (LIES BETWEEN THE CELLS)

PLASMA - 20% OF ECF (CONTAINED IN BLOOD VESSELS)

PLASMA IS THE FLUID PORTION OF BLOOD.

BLOOD IS PLASMA PLUS SUSPENDED BLOOD CELLS.

THE PLASMA EXCHANGES OXYGEN, NUTRIENTS, WASTES AND OTHER METABOLIC PRODUCTS WITH THE INTERSTITIAL FLUID SURROUNDING THE SMALLEST OF THE BLOOD VESSELS.

PLASMA HAS HIGHER PROTEIN CONCENTRATION THAN INTERSTITIAL FLUID, BUT OTHERWISE THEIR DISSOLVED SUBSTANCES ARE PRACTICALLY IDENTICAL.

70 KG PERSON (1 KG = 1 LITER)

42 KG WATER

28 KG INTRACELLULAR

14 KG EXTRACELLULAR

11 KG INTERSTITIAL

3 KG PLASMA