TISSUES

Key words

“Epi”= upon “Pseudo”= false “Squam” = scale “Strat”= layer Simple- one layer Stratified- multiple layers Cuboidal- cube shaped Columnar- rectangle shape- column Squamous- flat shape

Tissues

* a group of cells with specialized functions

Types: 1) Epithelial 2) Connective 3) Muscle 4) Nerve

Epithelial Tissues

Covers all free body surfaces Characteristics:

Lacks blood vessels, attached to a basement membrane, replaced continuously

Functions: protects, secretes, absorbs, excretes

Types of Epithelial tissues

Simple Squamous- single layer of flat cells Found: lungs, lines blood vessels, body

cavities

Types of Epithelial Tissue (cont.)

Simple cuboidal- single layer of cube shaped cells Found: kidneys and other glands

Types of Epithelial Tissue (cont.)

Simple columnar- single layer of elongated cells, nucleus is located near bottom of cell Contains microvilli- helps with absorption Contains goblet cells- secretes mucus Found: uterus, digestive tract

Types of Epithelial Tissues

Pseudostratified columnar- single layer of cells that look layered due to nuclei palcement cilia- to move mucus or sex cells Found: reproductive system, respiratory

system

Types of Epithelial Tissues

Stratified Squamous- many flat layers of cells, protects Found: skin, mouth, throat, vagina, anal canal

Types of Epithelial Tissues

Stratified cuboidal- layers of cube shaped cells, protects Found: mamary glands, sweat glands, slivary

glands, pancreas

Types of Epithelial Tissues

Stratified columnar- top layer is elongated, bottom layers are cube shaped, protects Found: male urethra, pharynx

Types of Epithelial Tissues

Transitional- specialized to change shape under tension Found: Bladder

Connective Tissue

General Characteristics: Support Protection Fills spaces Stores fat Produce blood cells Protect against infection Helps repair damaged tissue

Connective Tissue

Cells are separated by matrix (intercellular material)

Types of cells: Fibroblasts- produce collagenous and elastic

fibers Macrophages- are phagocytes (eat other cells

and materials) Mast cells- help with blood clotting and

immune response

Connective Tissue

Types of fibers in CT: Collagenous fibers- thick fibers made of

collagen, grouped in parallel bundles, holds tissues together, found in tendons

Elastic fibers- thin fibers, stretch easily, build networks, made of elastin

Reticular fibers- very thin fibers, delicate support

Connective Tissue- Loose fibrous

Forms delicate, thin membranes Has many fibroblasts Has a lot of collagenous and elastic fibers Function: Binds skin to tissue beneath

and provides nourishment to epithelial tissue, fills space between muscle

Connective tissue- Adipose

Type of loose connective tissue, Fat Function- protection, traps heat, and

energy stores in the body Found: beneath skin, around vital

organs, around joints. Note how nucleus is pushed to the side.

Connective tissue- Dense fibrous

Made of tightly packed collagenous fibers Function: Rigid structure, connects

tissues Found: tendons, ligaments, white of

eyes, deep layer of skin

Connective tissue- Hyaline, Elastic, fibrocartilage

Cartilage- rigid yet partially flexible Function: provides support, protects,

forms structure for developing bones 3 types of Cartilage Hyaline:

Fine collagenous fibers, chondrocytes, intercellular matrix- looks like white plastic

Found : ends of bone in joints, soft part of nose, rings of respiratory passage

Cartilage continued:

Elastic cartilage Made of dense network of elastic cartilage-

flexible Found: makes framework for ears, and parts

of larynx Fibrocartilage

Very tough tissue, contains many collagenous fibers

Shock absorbers Found between disks in vertebral column

Connective Tissue: Bone

Osteocytes, Intercellular matrix contains mineral salts and collagen, which makes bone rigid and collagen reinforces the mineral components

Function: structure, protection, provides framework

Found throughout whole body in skelton

Connective Tissue: Blood

Cells suspended in fluid matrix (plasma), red blood cells, white blood cells, platelets

Blood forms in red marrow of long bones Function: Transports, helps maintain

stable internal environment Found: throughout body in blood vessels

and heart chambers

Muscle Tissue

Characteristics: contract, move structures attatched to them

3 Types: Skeletal, Smooth, cardiac

Skeletal Muscle Tissue

Structure: Long cells (muscle fibers), striations

Function: attached to bones and helps with movement, can move by voluntary action

Muscle fibers contract when stimulated by nerves, then relax immediately.

Smooth Muscle Tissue

Structure: cells lack striations, short, spindle shaped

Function: muscle that works involuntary, constricts/ contracts to move things

Found: digestive system, bladder, blood vessels

Cardiac Muscle Tissue

Structure: cells are striated and joined end to end, has an intercalated disk between muscle fibers

Function: involuntary contractions in pumping blood

Found only in heart

Nervous Tissue

Structure: neuron (basic cell) has axons and dendrites, neuroglial cells (supports and binds nervous tissue)

Function: Sensitivity and conduction of nerve impulses

Found: Brain, spinal cord, peripheral nerves