bio 210 5-7 cram

What are the four main tissue types?

Epithelial: covers and lines; connective: supports and binds; muscle: contracts and moves; nervous: transmits signals.

What are the main functions of epithelial tissue?

Protection, absorption, secretion, filtration, and sensation.

What are the main characteristics of epithelial tissue?

Closely packed cells, polarity, basement membrane, avascularity, cell junctions, and regeneration.

What is epithelial polarity?

Apical surface faces a cavity, lumen, or exterior; basal surface attaches to the basement membrane.

Why is epithelial tissue avascular?

It lacks blood vessels; nutrients and oxygen diffuse from underlying connective tissue.

What are the functions of connective tissue?

Support, binding, protection, insulation, energy storage, and transport.

What makes up the extracellular matrix?

Ground substance and protein fibers such as collagen and elastic fibers.

What are the three types of muscle tissue?

Skeletal, cardiac, and smooth muscle.

What are the characteristics of skeletal muscle?

Voluntary, striated, usually multinucleated, and primarily attached to bones.

What are the characteristics of cardiac muscle?

Involuntary, striated, found in the heart, and connected by intercalated discs.

What are the characteristics of smooth muscle?

Involuntary, nonstriated, found in hollow organs and blood vessel walls.

What are the two main cell categories in nervous tissue?

Neurons transmit signals; neuroglia support and protect neurons.

How do endocrine and exocrine glands differ?

Endocrine glands are ductless and release hormones into the blood; exocrine glands release products through ducts.

What are examples of endocrine glands?

Pituitary, thyroid, and adrenal glands.

What are examples of exocrine glands?

Sweat, sebaceous, and salivary glands; pancreas.

What are the four body membranes?

Cutaneous, mucous, serous, and synovial.

What is the cutaneous membrane?

Skin, consisting of the epidermis and dermis; protects the body and limits water loss.

What is a mucous membrane?

Lines passages opening to the exterior; provides protection, secretion, and sometimes absorption.

What is a serous membrane?

Lines closed ventral body cavities and covers organs; secretes fluid that reduces friction.

What are examples of serous membranes?

Pleura around lungs, pericardium around the heart, and peritoneum in the abdominopelvic cavity.

What is a synovial membrane?

Lines the inner surfaces of movable joint cavities and produces lubricating synovial fluid.

What is atrophy?

Decrease in cell size, often causing a tissue or organ to shrink.

What is hypertrophy?

Increase in cell size, such as muscle enlargement with resistance training.

What is hyperplasia?

Increase in cell number, enlarging a tissue.

What is metaplasia?

Replacement of one differentiated cell type by another.

What is dysplasia?

Abnormal cell size, shape, and organization; may be precancerous.

What is simple epithelium?

Epithelium consisting of one cell layer.

What is stratified epithelium?

Epithelium consisting of multiple cell layers, usually for protection.

What is squamous epithelium?

Flat, thin cells; simple squamous allows diffusion and filtration.

What is cuboidal epithelium?

Cube-shaped cells commonly involved in secretion and absorption.

What is columnar epithelium?

Tall cells commonly involved in absorption and secretion.

What tissue forms the epidermis?

Keratinized stratified squamous epithelium.

What tissue forms the dermis?

Connective tissue; papillary layer is areolar, and reticular layer is dense irregular connective tissue.

What structures are found in the dermis?

Blood vessels, nerves, sensory receptors, hair follicles, sweat glands, and sebaceous glands.

What are five functions of the integumentary system?

Protection, temperature regulation, sensation, vitamin D synthesis, and limited waste excretion.

What is the hypodermis?

Subcutaneous tissue beneath the skin, mainly areolar and adipose tissue; anchors, cushions, and insulates.

What are the five epidermal strata from deep to superficial?

Stratum basale, spinosum, granulosum, lucidum, and corneum; lucidum occurs in thick skin.

Which cells produce melanin?

Melanocytes in the stratum basale; melanin helps protect against UV radiation.

How does skin regulate body temperature?

Sweating cools by evaporation; vasodilation releases heat, while vasoconstriction conserves heat.

How does skin contribute to vitamin D production?

UVB starts vitamin D3 production in skin; the liver and kidneys process it into active calcitriol.

What are the functions of nails?

Protect distal digits and assist grasping, scratching, and fine manipulation.

How do nails grow?

Cells in the nail matrix divide, keratinize, and push the nail plate forward.

What is onychomycosis?

A fungal nail infection that can cause discoloration, thickening, and brittleness.

What are the three major stages of wound healing?

Inflammatory, proliferative (migratory), and maturation/remodeling phases.

What happens during the inflammatory phase of wound healing?

A clot limits blood loss; inflammation removes debris and helps defend against infection.

What happens during the proliferative phase of wound healing?

Granulation tissue forms, new blood vessels grow, collagen is deposited, and epithelium covers the wound.

What happens during wound remodeling?

Collagen is reorganized and strengthened; the scar matures but usually does not regain full original strength.

What are the four bone classifications by shape?

Long, short, flat, and irregular bones.

What are examples of long bones?

Femur, humerus, and phalanges.

What are examples of short bones?

Carpals and tarsals; roughly cube-shaped and provide stability.

What are examples of flat bones?

Sternum, ribs, cranial bones, and scapulae.

What are examples of irregular bones?

Vertebrae and many facial bones.

What are the four main bone cell types?

Osteogenic cells, osteoblasts, osteocytes, and osteoclasts.

What do osteogenic cells do?

Divide and differentiate into osteoblasts.

What do osteoblasts do?

Build bone by producing osteoid, the unmineralized organic matrix.

What do osteocytes do?

Mature bone cells that maintain the matrix and sense mechanical stress.

What do osteoclasts do?

Resorb bone by breaking down its matrix.

What is appositional bone growth?

Bone increases in width as osteoblasts add bone beneath the periosteum while the inner surface is remodeled.

How does appositional growth differ from lengthwise growth?

Appositional growth increases width; lengthwise growth occurs at epiphyseal plates.

What is the epiphyseal plate?

Hyaline cartilage where long bones grow in length until the plate closes.

What is bone remodeling?

Continuous removal of old bone by osteoclasts and formation of new bone by osteoblasts.

What triggers parathyroid hormone (PTH) release?

Low blood calcium stimulates the parathyroid glands to release PTH.

How does PTH increase blood calcium?

Increases kidney calcium reabsorption, promotes bone resorption indirectly, and stimulates calcitriol production.

What is calcitriol?

The active form of vitamin D; increases intestinal absorption of calcium and phosphate.

How do PTH and calcitriol work together?

PTH responds to low blood calcium and stimulates calcitriol production; calcitriol increases intestinal calcium absorption.

What happens when blood calcium is high?

PTH secretion decreases; calcitonin may also help lower calcium.

What are the four stages of bone fracture repair?

Fracture hematoma, fibrocartilaginous (soft) callus, bony (hard) callus, and remodeling.

What happens during fracture hematoma formation?

Damaged vessels bleed, a clot forms, and inflammation begins.

What happens during soft callus formation?

Fibroblasts and chondroblasts produce collagen and cartilage that bridge the fracture.

What happens during hard callus formation?

Osteoblasts replace the soft callus with spongy bone, stabilizing the fracture.

What happens during fracture remodeling?

Osteoclasts remove excess bone and osteoblasts reshape it into stronger, organized bone.

What are the two major layers of the skin, and what tissue forms each?

The epidermis is keratinized stratified squamous epithelium; the dermis is connective tissue with papillary and reticular layers.

What are the five major functions of the integumentary system?

Protection, temperature regulation, sensation, vitamin D synthesis, and excretion of small amounts of waste.

How does the integumentary system protect the body?

Keratin and tightly joined cells limit water loss; the skin barrier helps block pathogens, chemicals, and physical injury; melanin helps protect against UV radiation.

How does the integumentary system regulate body temperature?

Sweat evaporates to cool the body; dermal vasodilation increases heat loss, while vasoconstriction reduces heat loss.

How does the integumentary system provide sensation?

Sensory receptors detect touch, pressure, vibration, pain, and temperature.

How does the integumentary system excrete waste?

Sweat removes small amounts of water, salts, and urea.

How does skin produce vitamin D3?

UVB radiation converts a cholesterol-derived precursor in the epidermis into vitamin D3, which is processed by the liver and kidneys.

What is calcitriol, and why is it important?

Calcitriol is active vitamin D; it increases intestinal absorption of calcium and phosphate and helps maintain blood calcium.

What are the main structures of a nail?

Nail plate, nail bed, nail matrix, lunula, eponychium (cuticle), and hyponychium.

What is the nail matrix, and why is it important?

The growth region containing dividing cells that produce the nail plate.

What is the lunula?

The pale, crescent-shaped visible region over the nail matrix.

What is the nail bed?

The skin beneath the nail plate that supports it.

How does onychomycosis affect the nails?

A fungal infection can cause thickened, discolored, brittle, or distorted nails.

What are the three main phases of wound healing, and what occurs in each?

Inflammatory: clotting and cleanup. Proliferative: granulation tissue, new vessels, collagen, and epithelial coverage. Remodeling: collagen reorganizes and strengthens.

What are the two layers of the dermis, and what tissue forms each?

Papillary layer: areolar connective tissue. Reticular layer: dense irregular connective tissue.

What happens during appositional bone growth, step by step?

Osteoblasts beneath the periosteum deposit new bone externally; osteoclasts resorb bone on the internal surface; remodeling maintains appropriate bone thickness and enlarges diameter.

What is the role of the periosteum in appositional growth?

The periosteum covers the outer bone surface and contains osteogenic cells that can become osteoblasts to add new bone.

How do osteoblasts and osteoclasts work together during bone growth?

Osteoblasts deposit bone matrix; osteoclasts resorb bone. Their coordinated activity increases bone size and reshapes it.

What is the stimulus for PTH release, and which glands release it?

Low blood calcium stimulates the parathyroid glands to release parathyroid hormone.

How does PTH affect the bones and kidneys?

It indirectly increases bone resorption and increases calcium reabsorption by the kidneys; it also promotes renal activation of vitamin D.

How does calcitriol affect the intestines?

It increases intestinal absorption of calcium and phosphate from food.

How do PTH and calcitriol work together to raise blood calcium?

PTH increases kidney calcium retention and stimulates calcitriol production; calcitriol increases intestinal calcium absorption, helping restore blood calcium.

What happens to PTH secretion when blood calcium rises?

PTH secretion decreases through negative feedback.

What is negative feedback in calcium regulation?

When blood calcium returns toward normal, the stimulus for PTH release decreases, reducing the response.

What are the four steps of bone fracture repair in order?

1. Fracture hematoma. 2. Fibrocartilaginous (soft) callus. 3. Bony (hard) callus. 4. Bone remodeling.