Exam 3 - Chapter 20

Stem Cell

Unspecialized cell that can divide, self-renew, and differentiate into specialized cell types.

Pluripotent

Ability of an embryonic stem cell to become any body cell type.

Animal

Multicelled organism; nearly all have cells organized into tissues.

Tissue

Group of one or more cell types plus extracellular matrix that perform specific tasks.

Epithelial tissue: Covers surfaces; lines cavities. Connective tissue: Supports, binds, protects. Muscle tissue: Enables movement. Nervous tissue: Detects stimuli and sends signals.

Four Tissue Types

Organ

Structure composed of two or more tissues working together for specific tasks.

Organ System

Organs and tissues that interact physically or chemically to perform a common task.

Homeostasis

Maintaining stable internal conditions the body's cells can tolerate.

Epithelial Tissue (Epithelium)

Sheetlike tissue with one free surface, tightly connected cells, no matrix between cells.

Exocrine Gland

Secretes substances (milk, sweat, saliva, oil) through a duct onto a surface.

Endocrine Gland

Ductless; secretes hormones into body fluids.

Connective Tissue

Most abundant tissue; extensive extracellular matrix; supports, binds, protects.

Soft Connective Tissue

Loose or dense tissue that holds body parts in place.

Fibroblast

Main cell in soft connective tissue; secretes collagen and matrix components.

Loose Connective Tissue

Few fibroblasts and fibers; most abundant type.

Dense Connective Tissue

Many fibroblasts and collagen fibers; stronger than loose connective tissue.

Cartilage

Cells in a rubbery matrix; cushions joints; supports nose and ears.

Adipose Tissue

Fat-storing tissue; stores energy, cushions, insulates.

Bone Tissue

Cells in calcium-hardened matrix; supports the body, produces blood cells.

Blood

Fluid connective tissue; transports gases, nutrients, wastes; has cells and plasma.

Muscle Tissue

Contracts in response to signals and moves the body.

Skeletal Muscle

Voluntary, striated, multiple nuclei.

Cardiac Muscle

Heart wall, involuntary, striated, single nucleus.

Smooth Muscle

Lines vessels/organs, involuntary, not striated, single nucleus.

Nervous Tissue

Detects stimuli, integrates information, controls responses.

Neuron

Excitable cell that transmits electrical signals.

Neuroglia

Support, protect, and assist neurons.

Body Cavities

Thoracic, abdominal, pelvic, cranial, spinal.

Skin (Organ)

Contains all four tissue types; protects body, makes vitamin D, senses environment, regulates temperature.

Epidermis

Outermost epithelial layer with melanin.

Dermis

Connective tissue layer with nerves and blood vessels.

Hypodermis

Loose connective + adipose tissue; contains larger blood vessels.

11 Human Organ Systems

(You likely need to recognize them: nervous, muscular, skeletal, circulatory, respiratory, endocrine, digestive, urinary, reproductive, integumentary, lymphatic/immune.)

Negative Feedback

A change triggers a response that reverses the change (e.g., body temperature regulation).