Chapter 1 ORGANIZATION AND GENERAL PLAN OF THE BODY

OVERVIEW AND TERMINOLOGY

Summary Definitions Organization of the human body Metabolism and Homeostasis

Negative feedback Positive feedback

Anatomical position and descriptive terms Body cavities Planes and sections

Definitions

Physiology –

Anatomy –

***These 2 are intimately linked – structures designed for particular functions.

?Pathophysiology-

Organization of the Human Body

Chemicals combine to form… Cells, similar cells combine to form… Tissues, two or more tissues combine

to form an… Organ, two or more work together as

an… Organ system, all organ systems work

together to support the… Organism

Figure 1.1

Chemicals

Simplest chemical is an element, 20 are found in the human body.

Each element is composed of unique atoms.

Atoms combine to form molecules and compounds: Inorganic – Organic –

Chemicals

Molecules & compounds combine to form macromolecules.

Organic macromolecules in living organisms:

Cells

Smallest living structural and functional units.

Composed of organic macromolecules.

Tissues

Groups of cells with similar structure and function.

4 basic groups: Epithelial tissue – Connective tissue –

Muscle tissue - Nerve tissue –

Organs

2 or more tissues that combine to form a structure that performs a particular function. Examples - Heart Lungs ????

Organ System

Group of organs that all contribute to a certain body function. Cardiovascular system ?????

11 organ systems: study Table 1-1, p.7 and Figure 1-2, pp. 8-9.

Organ Systems Integumentary system: skin; protects us

from chemicals, sun, and pathogens. Skeletal system: bones and ligaments;

protects internal organs, provides framework for muscles, supports the body.

Muscular system: muscles and tendons; moves the skeleton, produces heat, moves blood and food.

Organ Systems

Nervous system: brain, spinal cord, peripheral nerves, sensory organs; collects and interprets sensory information, regulates body functions.

Endocrine system: glands, produce hormones that regulate body functions.

Organ systems

Circulatory system: heart, blood vessels and blood; transports oxygen and nutrients to tissues.

Lymphatic system: lymph glands and vessels; destroys pathogens and returns tissue fluid to circulatory system.

Organ Systems

Respiratory system: lungs, trachea, etc.; exchanges O2 and CO2 between the body and the atmosphere.

Digestive system: stomach, intestines, liver, etc.; breaks down food into nutrients and absorbs them into the blood stream.

Organ Systems

Urinary System: kidneys, urinary bladder, urethra; removes waste products from the blood.

Reproductive system: ovaries, testes, uterus, prostate gland; produces eggs or sperm, female provides site for developing offspring.

Metabolism

Sum of all chemical reactions and processes in the body.Anabolism – Catabolism –

Causes changes internally and externally. Ex. Digestion can cause an increase in blood glucose, etc.

Homeostasis

A state of relative stability within the body despite changes in the external and internal environment.

Maintenance Mechanisms: Negative feedback – blood sugar and

temperature regulation. Positive feedback – fever, blood clotting

and labor.

Negative Feedback

Sequence:Stimulus is “sensed” by a receptorReceptor relays information to a control

centerControl center evaluates and creates a plan

of actionPlan sent to effectorEffector eliminates the stimulus (corrects

problems)

Figure 1.4

Figure 1.5

Negative Feedback – Temperature Control

Positive Feedback

Sequence Same as for negative feedback except

effector does NOT eliminate the stimulus, it increases it.

Requires an external “brake”.

Anatomical Position andDescriptive Terms

Anatomical position: standing upright, facing forward, arms at the sides palms facing forward, feet slightly apart.

Table 1-2 Descriptive Terms and Table 1-3 Terms of Location and Position

***Know these terms and how to use them for the quiz and test 1.

Table 1.1.1

Table 1.1.2

Body Cavities and Membranes

2 major body cavities Dorsal (posterior) cavity – 2 sections

Cranial – Vertebral or spinal –

The two sections are continuous and lined by membranes called meninges.

Body Cavities and Membranes

2 body cavities cont’d Ventral (anterior) Cavity – two major

compartments separated by the diaphragm. Thoracic cavity –

Abdominal cavity

Pelvic cavity

Body Cavities and Membranes

2 body cavities cont’d Ventral (anterior) Cavity Membranes

Thoracic cavity: Parietal pleura lines the chest wall, visceral

pleura covers the lungs Visceral pericardium covers the heart and the

parietal pericardium lines the sac around the heart.

Body Cavities and Membranes

2 body cavities cont’d Ventral (anterior) Cavity Membranes

Abdominal cavity: The peritoneum is a membrane the lines the

abdominal wall and continues into the ... The mesentery covers the outer surfaces of the

abdominal organs.

Planes and Sections

Use: to describe internal anatomy, orientation points, increase visibility.

Plane: an imaginary flat surface that separates two portions of the body, fig 1-6.

Planes and Sections

Sections: cuts in a body or organ or plane that make the structures more easily visible. Frontal or coronal section – separates the

body into front and back sections. Sagittal section – separates the body into

right and left portions. Transverse section – separates the body

into upper and lower sections.

Planes and Sections

o Other terms that usually refer to organs:o Cross sectiono Longitudinal section

Areas of the Abdomen Division into 4

quadrants, fig 1-7 RUQ LUQ RLQ LLQ

Areas of the Abdomen 9 regions, fig 1-7

Upper areas: left hypochondriac, epigastric, right hypochondriac.

Middle areas: left lumbar, umbilical, right lumbar.

Lower areas: left iliac, hypogastric, right iliac.