Anatomy and Physiology: Tissues, Skin, and Skeletal System

Tissues

Groups of similar cells that perform a specific function.

Four major tissue types

Connective, Muscle, Epithelial, Nervous (CMEN).

Three intercellular junctions

Tight (no leaks), Desmosomes (strong/flexible), Gap (communication).

Epithelial cells packing

Tightly packed.

Location of epithelial tissue

Covers body, lines organs, forms glands.

Epithelial tissue blood vessels

No, it's avascular (gets nutrients from connective tissue).

Simple vs. Stratified epithelium

Simple = one layer; Stratified = multiple layers.

Squamous vs. Cuboidal vs. Columnar

Squamous = flat, Cuboidal = cube, Columnar = tall.

Glandular epithelium

Epithelium specialized for secretion (sweat, oil, hormones).

General characteristics of connective tissue

Found everywhere, loosely packed cells, lots of matrix, vascular (except cartilage).

Matrix in connective tissue

Extracellular ground substance + fibers.

Fibers in connective tissue

Collagen (strength), Elastic (stretch), Reticular (support).

Cells that make fibers

Fibroblasts.

Connective tissue cell types

Fibroblasts, macrophages, adipocytes.

Connective tissue blood vessels

Usually yes (cartilage = no, ligaments/tendons = low).

Purpose of muscle tissue

Movement.

Three types of muscle tissue

Skeletal (voluntary, striated), Cardiac (heart, striated, branched), Smooth (organs, involuntary, no striations).

Location of nervous tissue

Brain, spinal cord, nerves.

Major nervous tissue cell types

Neurons (signals) & Neuroglia (support).

Integumentary system components

Skin, hair, nails, glands.

Another name for skin

Integument.

Functions of skin (PSSB)

Protect, Sense, Sweat (regulate temp), Barrier.

Epidermis type of epithelial tissue

Stratified squamous epithelium.

Separation of epidermis and dermis

Basement membrane.

Layers of epidermis (outer → inner)

Corneum, Lucidum (thick skin only), Granulosum, Spinosum, Basale (C.L.G.S.B.).

Layer that divides

Basale.

Layer that is dead and flakes off

Corneum.

Epidermis blood vessels

No; nutrients come from dermis.

Keratinization

Cells fill with keratin, die, and harden.

Melanocytes function and location

Make melanin (UV protection), in stratum basale.

Purpose of melanin

Protect from UV → prevents skin cancer.

Dermal papillae

Finger-like projections → grip, fingerprints.

Two dermis layers

Papillary (loose CT, touch) and Reticular (dense irregular CT, strength).

Hypodermis part of skin

No.

Tissue that makes up hypodermis

Adipose.

Functions of hypodermis

Cushion, insulate.

Cushion

Insulate.

Accessory structures origin

Epidermis.

Function of nails

Protection; nail plate, nail bed, root.

What is hair?

Keratinized cells.

Parts of hair

Shaft, root, bulb.

Function of arrector pili muscle

Goosebumps.

Sebaceous glands produce

Sebum (oil) → keeps skin soft & waterproof.

Types of sweat glands

Eccrine (everywhere, temp), Apocrine (armpits/groin, stress/puberty).

What is the skeletal system?

Bones, joints, cartilage, ligaments.

Functions of bones (SPMBS)

Support, Protect, Movement, Blood production, Store minerals.

Shapes of bones

Long (humerus), Short (carpals), Flat (skull), Irregular (vertebrae), Sesamoid (patella).

Long bone major parts

Epiphysis (ends), Diaphysis (shaft), Metaphysis (between), Medullary cavity (marrow).

Connective tissue components of long bone

Articular cartilage (joint), Periosteum (outer covering), Endosteum (lining cavity), Bone marrow (red = blood, yellow = fat).

Bone cells

Osteoblasts (build), Osteoclasts (break), Osteocytes (maintain).

Matrix components

Collagen (flexible), Calcium salts (hard).

Compact bone components

Osteons, central canal, lamellae, canaliculi.

Spongy bone components

Trabeculae, spaces with marrow.

Compare compact vs spongy bone

Compact = dense, outer layer; Spongy = porous, inside, lighter.

When do bones grow?

Childhood → early adulthood.

Intramembranous ossification makes which bones?

Flat bones (skull, clavicle).

Endochondral ossification makes which bones?

Most bones (replace cartilage model).

Primary ossification center

Diaphysis.

Secondary ossification center

Epiphysis.

What is the epiphyseal plate?

Growth plate; zones of cartilage for length growth.

Why can't bones grow after plate ossifies?

Cartilage replaced by bone → no more length growth.

Hormone for bone growth

Growth hormone (GH).

What happens if GH is too high/low?

Gigantism/dwarfism.

Bone fracture types

Simple (closed), Compound (open).

Steps of bone fracture repair

Hematoma → callus → bone → remodel.

What is bone remodeling?

Continuous replacement of old bone with new.

Osteopenia vs Osteoporosis

Osteopenia = low bone density; Osteoporosis = brittle, weak bones.

Effect of exercise on bone

Strengthens bones (more mass).

Why must blood calcium be regulated?

For muscle & nerve function.

PTH vs Calcitonin

PTH ↑ blood Ca; Calcitonin ↓ blood Ca.

How many bones in adult?

~206 (varies).

What are sutural and sesamoid bones?

Sutural = skull seams, Sesamoid = in tendons (patella).

Axial vs Appendicular skeleton

Axial = skull, spine, ribs; Appendicular = limbs, pelvis, shoulder.

Purpose of cranium vs facial skeleton

Cranium = protects brain; Facial skeleton = shape, attachment for muscles.