Bio 243

Epithelial tissue

One of the four basic tissue types that covers body surfaces and lines cavities.

Connective tissue

One of the four basic tissue types that supports, binds together, and protects tissues and organs.

Muscle tissue

One of the four basic tissue types responsible for movement.

Nervous tissue

One of the four basic tissue types that transmits impulses for communication.

Ectoderm

The outermost germ layer formed during gastrulation.

Mesoderm

The middle germ layer formed during gastrulation.

Endoderm

The innermost germ layer formed during gastrulation.

Interstitial fluid

The fluid that surrounds cells, mediating exchange between blood and cells.

Homeostasis

The maintenance of a stable internal environment.

Negative feedback mechanism

A response that reduces or shuts off the original stimulus.

Acidosis

Arterial blood pH < 7.35.

Alkalosis

Arterial blood pH > 7.45.

Buffers

Molecules that resist changes in pH.

Thyroid hormone

The major metabolic hormone that regulates metabolism, growth, and blood pressure.

Growth hormone (GH)

Stimulates body growth, protein synthesis, and metabolism.

Adrenal cortex

The outer layer of the adrenal gland that produces aldosterone, cortisol, and androgens.

Compact bone

Type of bone that is dense and forms the outer layer of bones.

Spongy bone

Type of bone that has a porous structure and is found inside bones.

Osteoblasts

Cells that build new bone tissue.

Osteoclasts

Cells that break down bone tissue.

Parathyroid hormone (PTH)

Hormone that increases blood calcium levels.

Calcitonin

Hormone that lowers blood calcium levels.

Passive transport

Movement of molecules without energy input.

Diffusion

Movement of molecules from high to low concentration.

Active transport

Movement of molecules using ATP.

Endocytosis

The process of engulfing substances into the cell.

Exocytosis

The process of expelling substances from the cell.