CHAPTER 1

THE HUMAN BODY: AN ORIENTATION

ANATOMY – is the study of the structure and shape of the body parts and their relationships to each other.

-Gross Anatomy-large structures, easily

easily observable

-Microscopic Anatomy-very small structures; can only be

viewed with a microscope

Cytology-study of cells

Histology-study of tissues

PHYSIOLOGY – study of how the body and its parts work or

function

RELATIONSHIP BETWEEN ANATOMY AND PHYSIOLOGY

Are always related; the shape or structure of a body part determines its function. Example: the heart is a pump, lungs are shaped for gas exchange.

LEVELS OF STRUCTURAL ORGANIZATION

Fig. 1.1 p.3

1. Chemical level – atoms(building blocks of matter) combine

to form molecules

2. Cellular level – molecules combine to form cells, the smallest

unit of living things

3. Tissue level – consists of groups of similarly shaped cells

that have a common function. Ex.-muscle tissue, epithelial

tissue, nervous tissue, and connective tissue

4. Organs – are composed of two or more tissue types that have

a specific function. Ex.- stomach, small intestine, heart

5. Organ System – is a group of organs. Ex. – digestive system,

skeletal system, cardiovascular system

6. Organism – in our case, humans, is made up of 11 organ

systems and it is the highest level of structural organization

ORGAN SYSTEM OVERVIEW

Pages 5,6 (Know functions and structures)

1. Integumentary

Forms the external body covering

Protects deeper tissue from injury

Synthesizes vitamin D

Location of cutaneus nerve receptors

2 Skeletal

Protects and supports body organs

Provides muscle attachment for movement

Site of blood cell formation

Stores mineral

3. Muscular

Allows locomotion

Maintains posture

Produces heat

4. Nervous

Fast-acting control system

Responds to internal and external changes(stimuli)

Activates muscles and glands

5. Endocrine

Slow-acting control system

Secretes regulatory hormones for

growth, reproduction, metabolism

6. Cardiovascular

Transports materials in body via blood pumped by

heart. Materials like oxygen, carbon dioxide, nutrients,

and wastes

7. Lymphatic

Returns fluids to blood vessels

Disposes of debris

Involved in immunity

8. Respiratory

Keeps blood supplied with oxygen

Removes carbon dioxide

9. Digestive

Breaks down food

Allows for nutrient absorption into blood

Eliminates indigestible material

10. Urinary

Eliminates nitrogenous wastes

Maintains acid – base balance

Regulates water and electrolytes

11. Reproductive

Production of offspring

MAINTAINING LIFE – Organ systems are interrelated (Fig 1.3, p.8)

NECESSARY LIFE FUNCTIONS

1. Maintain Boundaries- every living thing must be able to keep whats inside separate from what is outside. Cells maintain boundaries by having a plasma membrane; the integumentary system protects the internal organs from drying out, from bacteria, heat, sunlight, and chemical substances.

2. Movement

Locomotion

Movement of substances

3. Responsiveness

Ability to sense changes and react

4. Digestion

Break-down and delivery of nutrients

5. Metabolism – all the chemical reactions in the body, breaking

down substances and building substances

Production of energy

Making body structures

6. Excretion

Elimination of waste from metabolic reactions

7. Reproduction

Production of future generation

8. Growth

Increasing of cell size and more often growth is by

increasing the number of cells. For growth to occur, cell

construction must occur faster than cell destruction.

SURVIVAL NEEDS

1. Nutrients

Chemicals for energy and cell building.

Includes carbohydrates, proteins, lipids, vitamins,

And minerals

2. Oxygen

Required for chemical reactions. Most of energy produced

in the body uses oxygen

* Most important survival need

3. Water

60-80% of body weight

Most abundant chemical substance in the body

Provides the fluid base for body secretions and excretions

Provides for metabolic reaction

4. Stable body temperature

Chemical reactions affected

5. Atmospheric pressure must be appropriate – is the force

Exerted on the surface of the body by the weight of the air. The function of breathing depends on the appropriate atmospheric pressure.

HOMEOSTASIS

Describes the body’s ability to maintain a relatively stable internal

environment even though the world outside the body is changing.

We have to maintain a dynamic state of equilibrium inside the body.

MAINTAINING HOMEOSTASIS

The body communicates through neural and hormonal control

Systems (Fig. 1.4 p. 10)

1. Receptor – responds to changes in the environment (stimuli)

sends information to control center

2. Control Center

Determines set point. Analyzes information. Determines

appropriate response.

3. Effector

Provides a means for response to the stimulus

FEEDBACK MECHANISMS

Negative Feedback Mechanisms – most homeostatic mechanisms are negative feedback. The response shuts off original stimulus or reduces its intensity. Works like a household thermostat. Ex.-glucose levels, oxygen and carbon dioxide levels, body temperature, etc.

Positive Feedback Mechanisms – this type of feedback tends to enhance the original stimulus to push the variable farther. In the body this only occurs in blood clotting and birth of a baby.

HOMEOSTATIC IMBALANCE

If homeostasis is not maintained in the body then the imbalance can cause disease and can even cause death. As our bodies age, our body organs become less efficient and our internal conditions become less and less stable. These events place us at an even greater risk for illness.

THE LANGUAGE OF ANATOMY (IN LAB)