Basic Structure of the Human Body and Parts of a Cell

7:1 Basic Structure of the Human Body The normal function of the human body is compared to an organized machine The machine malfunctions, disease occurs. Anatomy: study of form and structure. Physiology: study of why and how living organisms work. Pathophysiology: study of how disease occurs and body’s response Protoplasm – Makes up all living things.

Cells Microscopic Structures Carry on all functions of life.

Functions of Cells Take in food and oxygen Produce heat and energy Move and adapt to environment Eliminate wastes Perform special functions Reproduce to create identical cells

Basic Parts of Cells Cell membrane – outer protective covering of cell Semipermeable Cytoplasm – semifluid inside cell where all chemical reactions occur Organelles – located in the cytoplasm and help cell to function

Organelles Nucleus – “brain” of cell, controls many cell activities, important in cell reproduction. Nucleolus – Located in nucleus. Important in cell reproduction. Manufactures ribosomes which aid in synthesis (production) of protein Chromatin – Located in nucleus, made of deoxyribonucleic acid (DNA) and protein. Chromatin condenses to form chromosomes during cell reproduction. Chromosomes carry genes which carry inherited characteristics.

Organelles, cont. Centrosome – located in cytoplasm and near the nucleus. Contains two centrioles important in cell reproduction. Mitochondria – located throughout cytoplasm, “furnace” or “Power House” of the cell. Produces adenosine triphosphate (ATP) which is the major energy source of the cell. Golgi Apparatus – stack of membrane layers located in the cytoplasm. Produces, stores, and packages secretions for discharge from cell.

Organelles of a cell, cont. Endoplasmic Reticulum – located in cytoplasm. Allows for transport of materials in and out of the nucleus. Aids in synthesis and storage of proteins. Lysosomes – Found throughout cytoplasm. Contains digestive enzymes that digest and destroy old cells, bacteria and foreign materials. Pinocytic Vesicles – Pocket-like folds in cell membrane. Allow large molecules such as protein and fat to enter cell then folds closed to form vacuoles or bubbles in cytoplasm

Cell Reproduction Mitosis – Reproduce by dividing into two identical cells, asexual reproduction. Meiosis – Reproduction of sex cells (gametes). Produces ovum and sperm.

Tissues Cells contain same basic parts but vary in shape, size, and special function. Cells of same type join together for common purpose to form tissue. Tissue Fluid –water with various dissolved substances which makes up 60% - 99% of tissue Dehydration – Insufficient amount of tissue fluid Edema – Excess amount of tissue fluid; results in swelling of tissue

Types of Tissue Epithelial – Covers surface of body, main tissue in skin, also forms lining of intestines, respiratory, and urinary tracts; forms body glands

Types of Tissue, Connective Connective – Supportive fabric of organs and other body parts Types of Connective Tissue Soft - adipose (fatty) tissue stores fat as food reserve which is source of energy insulates body and acts as padding

Types of Tissue, Connective Hard Cartilage – tough, elastic material found between bones of spine and at end of long bones. Acts as shock absorber. Also found in nose, ears, and larynx Bone – Forms rigid structure of human body. Has calcium salts, nerves, and blood vessels.

Types of Tissue, Connective Liquid Blood – carries nutrients and oxygen to cells and carries metabolic waste away from cells. Lymph – transports tissue fluid, proteins, fats and other material from tissues to circulatory system.

Types of Tissue Nerve – made up of neurons which transmit messages throughout body; composes nerves, brain, and spinal cord

Types of Tissue, Muscle Muscle – produces power and movement by contraction of muscle fibers Types of Muscle Tissue Skeletal – attaches to bones and provides for movement of body Cardiac – causes heart to beat Visceral (smooth) – present in walls of organs such as stomach, intestine, and blood vessels

Organs and Systems Organ – two or more tissues joined together to perform specific function System – organs and other body parts joined together to perform a particular function

Summary Cells combine to form tissues. Tissues combine to form organs. Organs and other body parts combine to form systems.