Anatomy Unit 2 - Cell Types and Tissues

What are the four major tissue types?

epithelial, connective, muscle, nervous

epithelial tissue

protective covering, function in absorption and secretion

Epithelial tissues always have a _______ and ______.

free surface and basement membrane

Epithelial tissues line _____ and ______.

hollow organs and body cavities

desmosomes

junctions between adjacent cells

Epithelial tissue cells are classified by…

number of layers and shape of cells

simple squamous

• single layered flat cells

• nutrients cross barrier easily

• located in air sacs and blood vessels (capillaries)

simple cuboidal

• single layered cube cells

• lines kidney tubules

• lines ducts to glands

• secretes and reabsorbs molecules

simple columnar

• single layered column cells

• nuclei near basement membrane

• contains goblet cells that produce/secrete mucus

• lines intestines and stomach to absorb nutrients

• contains cilia or microvilli

pseudostratified columnar

• column cells that appear multilayered (NOT!)

• nuclei are at different levels

• can have cilia and microvilli

• respiratory lining/nasal passage

stratified squamous

• multilayered flat cells

• tops cells are flat and bottom cells are rounded

• protects against abrasion

• lines cavities that open to the outside

• found in outer layer of skin

stratified cuboidal

• multilayered cube cells

• 2-3 layers of cells

• found in mammary, saliva, and sweat glands

• secretes water and ions

stratified columnar

• multilayered column cells

• lines male urethra and pharynx

• secretes mucus

transitional tissue

• goes through repeated cycles of stretching w/o damage

• bladder

glandular epithelium

• made up of specialized substances that secrete something

• ex: endocrine and exocrine glands

Endocrine glands are _____.

ductless

merocrine glands

• fluid products released w/o damage to cell

• exocrine gland

• saliva and sweat

apocrine glands

• scented glands

• cells decapitate (die) when products are released

• armpits and groin

holocrine gland

• secretory product that are whole cells

• sebaceous glands

connective tissue

support body parts through stabilization, bind structures together

What is the most abundant and diverse tissue type?

connective tissue

Connective tissues have _____ matrix.

ground

What are the 3 basic components of connective tissue?

1. specialized cell

2. protein fibers

3. ground matrix

fibroblasts

• most common connective tissue cell type

• fixed cells - stay in its home

• large and star shaped

• produce connective fibers

macrophages

• not fixed - wanders throughout body

• phagocytosis - eating debris/bacteria

• aides immune system

mast cells

• fixed cells

• release heparine and/or histamines - helps with allergies

• release antibodies

• destroying invading micro-organisms

collagen fibers

• thick, long, straight, unbranched

• hold structures together

• found in dermis (deep layer of skin)

• helps make up tendons and ligaments

elastic fibers

• wavy and branched

• located in vocal cords

• can stretch but return to original shape w/ no damage

reticular fibers

• super thin, interwoven framework, highly branched

• found in lymph nodes

• forms a supportive network

What are 3 characteristics of connective tissue proper?

1. dispersed cells

2. extra cell material is greater than the number of cells

3. extensive protein fibers

loose connective/areolar tissue

• mainly made of fibroblasts w/ some collagen and elastic fibers

• beneath epithelial tissue so it can bind skin to deeper structures

• found between muscles

• provides support and cushion

• vascular (has blood flow)

• provides epithelium w/ nourishment

• anchors blood vessels and nerves

adipose

• fat cells

• made up of adipocytes

• cushions and insulates

• stores fat

• nucleus is pushed to side

• energy storage

reticular connective tissue

• composed of reticular fibers

• support structure for organs (kidney, liver, spleen)

dense connective tissue

• dense, strong, durable

• resists tension

• capsule around organs

• lines join cavities

• poor blood supply

elastic connective tissue

• mainly elastic fibers w/ some collagen and fibroblasts

• form attachments between bones

• lines walls of airway, heart, and arteries

• can stretch w/o damage and return to original size

osseous tissue (bone)

• contains osteocytes and solid matrix

• supports and protects soft tissues

• form blood cells

• weightbearing

• resistant to shattering

• constantly replacing damaged cells

cartilage

• chondrocytes in lacunae (gap/space)

• rigid matrix

• poor blood supply

• shock absorption

hyaline cartilage

• solid-gel matrix that resembles white glass

• located at the ends of bones

• makes up embryotic skeleton

elastic cartilage

• flexible

• external ear and larynx

• extremely resilient

fibrocartilage

• very tough - contains collagenous fibers

• shock absorber

• vertebral disc and pubic symphysis

blood

• composed of RBC, WBC, and platelets

• fluid matrix - plasma

• aides in transport, clotting (platelets), and defense

muscle tissue

supports body movements and contains skeletal structure

What are the cells of muscle tissue?

muscle fibers

Muscle tissue contains _____ cells.

contractile

skeletal muscle

• striated - made up of actin and myosin

• voluntary movement

• located anywhere attached to bone

• muscle fibers are large and multinucleated

• cells don’t divide

smooth muscle

• non-striated

• involuntary movement

• makes up digestive organs

• nervous system isn’t necessary for function

cardiac muscle

• heart (duh)

• striated

• involuntary movement

• muscle fibers branch

• cells attached by intercalated discs

• maintain blood pressure

• pacemaker for resting heartrate requires no nervous system

• increase/decrease in heartrate needs nervous system

nervous tissue

communication and conducting impulses

What are the basic cells of nervous tissue?

neurons

Neurological cells ____ and _____.

bind and support

Neurons conduct ________.

nerve impulses

What is the control center of nervous tissue?

brain and spinal cord

What are the 3 parts of a neuron?

1. dendrites: receive signal

2. cell body: houses nucleus

3. axon terminal: what the signal travels down

serous membranes

• line internal body cavities

• cover organs

• made of simple epithelium and connective tissues

• visceral, parietal, pericardium

mucous membrane

• open to external environment

• lines tubes and openings

cutaneous membrane

• completely external

• skin - epidermis and dermis

• made of stratified squamous and connective tissues

• thick, dry, somewhat waterproof

synovial membrane

• located between bones

• made entirely of connective tissue

• makes up joints that allow free movement

• contains synovial fluid - reduces friction

Which muscle is striated and involuntary?

cardiac muscle

Which glands make their product by breaking down entire cells?

holocrine

organelles

cellular components that carry out specific tasks necessary for the cell's life processes

basement membrane

complex structures separating epithelial and connective tissue

neuroglia

supporting cells for nervous system

apoptosis

genetically controlled cell death

What are the 3 major components of any cell?

1. cell membrane

2. nucleus

3. cytoplasm

Why do we say the plasma membrane is selectively permeable?

allows some substance to pass through while blocking others

What makes the plasma membrane selectively permeable?

structure - phospholipids are arranged where the hydrophobic tails are facing inward and packed together tightly, blocking any large molecules from passing through

diffusion

movement of molecules from an area of high concentration to an area of low concentration

osmosis

process where water molecules move through selectively permeable membrane to an area with low concentration

facilitated diffusion

allows molecules and ions to move across a cell membrane w/ help from proteins

passive transport

diffusion of molecules from high to low concentration

active transport

diffusion of molecules from low to high concentration

vesicle

small, saclike organelle that contains substances to be transported within the cell or secreted

phosphate head

hydrophilic end of phospholipid molecule

phagocytosis

process by which a cell takes in solid particles

pinocytosis

process by which a cell takes in tiny droplets of liquid

excretion

getting rid of waste products

secretion

releasing substances from cells and glands

What factors cause cells to divide?

1. telomeres shortening

2. miotic clock telling cells to stop dividing

3. hormone and growth factors

Why do cells divide?

growth, replace dead cells, maintain tissue renewal

daughter cells

cells created when a cell divides