Human Anatomy and Physiology

20A-2

Anatomy and Physiology

• Anatomy ~ how a structure is shaped, where it is found and of what it is made.

• Physiology ~ concerned with the function of a structure

• Anatomical position ~ a person standing, arms at side, with toes, palms and face facing forward. Giving the direction and area on a human body using terms based on the body being in the anatomical position.

Sagittal: divides body into right and left portions

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Levels of Organization of Multicellular Organisms

1. Cells ~ the basic unit of structure and function of living organisms

2. Tissues ~ similar cells that are grouped together to perform a similar function

3. Organs ~ tissues grouped together to perform a specific function. One organ may contain more than one type of tissue. The heart contains tissues from all four groups.

4. Organ Systems ~ Groups of organs working together to accomplish life functions.

Subatomic

Atomic

Molecular

Organelle

Cellular

Tissue NervousTissue

Brain

NervousSystem

PronghornAntelope

Organ

Organ System

Organism

PopulationHerd of Pronghorns

Hawk

Water

Earth’ssurface

Community

Ecosystem

Biosphere

Pronghorns

Hawk GrassPronghornsSnakeBushes

SoilAir

Snake

Histology• Histology ~ the study of tissues• Vascular tissues- blood vessels run through

them (ex. Muscle tissue)• Avascular tissues- lack blood vessels (ex.

Epithelial tissue)

4 Types of Tissue

• Connective• Epithelial• Muscle• Nervous

Connective Tissue

• Most abundant and diverse• Support, connect, and protect other body

structures• Usually connective tissue cells are not

adjacent to each other, but have matrix between them.

Types of Connective Tissue

• Bone• Cartilage• Dense fibrous (ligaments and tendons)• Loose fibrous• Adipose (fat)• Blood• Lymph• Hemopoietic (blood forming)

Connective TissueMatrixes

Matrix ~ nonliving material present in tissue, which is secreted by the tissue’s cells

Four types of matrix1. solid matrix ~ example: bone2. fluid matrix ~ example: blood ~ carries blood cells3. fibrous matrix ~ example: ligaments and tendons

~ permits flexibility4. gel matrix ~ example: cartilage of nose and ear ~

soft mixed with fibers

Blood Adipose (fat)

Cartilage Bone

Tendons and Ligaments

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Epithelial Tissue

• Layers of cells that cover or line the external and internal surfaces

• Vary in thickness from a single layer lining capillaries to multiple layers forming the skin.

• Covers and lines to protect, secrete, absorb and filter

BladderTrachea

Skin

Muscle Tissue

• Cells contract• Move body or move fluid through the body• 3 types– Skeletal– Smooth- typically involuntary– Cardiac

Skeletal Muscle: Note that the cells (running vertically) are long, straight, striated and multinucleated.

Cardiac Muscle: Note that the cells are much more branching than skeletal muscle, but are still striated. The key feature is the dark lines that run across the tissue between cells. These are intercalated discs and are only found in cardiac muscle.

Smooth Muscle: Note that striations are not present (thus the name) and that the cells are flattened and stretched out (spindle shaped).

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Nervous Tissue

• Cells receive and transmit electrochemical impulses from muscles, glands, and other nerve cells

• Brain, spinal cord, and nerves• Coordinates muscular movements, interprets

sensations received from the environment, and controls thought processes and emotions

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Organ Systems

• Integumentary• Skeletal• Muscular• Respiratory• Digestive• Circulatory• Lymphatic

• Excretory• Nervous• Endocrine• Reproductive

Body Cavities

1. Cranial cavity ~ houses the brain2. Spinal cavity ~ surrounds the spinal cord3. Thoracic cavity ~ contains the heart,

respiratory organs and esophagus4. Abdominal cavity ~ contains the digestive,

reproductive and excretory organs*The thoracic cavity and abdominal cavity are

separated by the diaphragm.