Tissues -- Anatomy and Physiology

Definition of a tissue

groups of cells similar in structure and function

4 main types of tissues and their locations

1) Epithelial -- found on external surfaces and internal cavities

2) Connective tissue -- cells and matrix that structure and anchor

3) Muscle Tissue -- cells that receive contact and cause movement

4) Nervous tissue -- receive/process/transmit messages

Epithelial tissue functions

protection, absorption, filtration, excretion, secretion, and sensory recognition.

Epithelial tissue characteristics

*** apical-basal polarity

apical = top and exposed to the outside

basal = bottom and attached to the lower tissue membranes

*** on top of connective tissue

+++ avascular

Squamous

flat, scale-like epithelial cell

Cubodial

cube-shaped epithelial cells

Columnar

column-shaped epithelial cells

Simple

1 layer

Stratified

more than one layer

pseudostratified

one layer but appears to be multilayer because cells are different lengths

Transitional

several layers

9 types of epithelial tissue

simple squamous, simple cuboidal, simple columnar, pseudostratified columnar, stratified squamous, stratified cuboidal, stratified columnar, transitional epithelium, glandular

Simple squamous epithelium

single layer of flattened cells

located in lining capillaries (small blood vessels), alveoli (air sacs), glomeruli (kidney blood vessels), mesothelium (around abdominopelvic areas)

Allowing diffusion and absorption.

Simple Cubodial Epithelial Tissue

single layer of cube shaped cells

kidney tubules, ducts of glands, ovaries, and seminiferous tubules

secretion and absorption

simple columnar epithelium

single layer of column shaped cells

Non-ciliated are responsible for secretion and absorption in the digestive tract, ducts of glands

Ciliated are responsible for movement of the uterus and oviducts.

Pseudostratified epithelial

single layer which appears to be many

located in the upper respiratory tract and reproductive system

allowing for secretion and movement

Stratified squamous epithelium

more than one thin layer of cells

Keratinized = skin

Non-keratinized = mouth, vagina, rectum

Protection from abrasions

stratified cuboidal epithelium

more than one layer of cube shaped cells

salivary glands, sweat glands, mammary glands

Secretion and strengthening of glands

Stratified Columnar Epithelium

more than one layer of column-like cells

pharynx, urethra, conjunctiva

protection and secretion

Transitional epithelium

several layers which stretches and protects the urinary bladder from urine.

Glandular Epithelium

composed of cells that ae specialized to produce and secrete chemical substances

-- endocrine and exocrine

Endocrine glands

secrete into the bloodstream

-- hormones

Exocrine glands

excrete out of the body or an organ or ducts

-- sweat, saliva, mucus, digestive enzymes

Tight junction

form a leak-proof barrier ; found in areas where fluids need to be kept separate (ex the BBB)

Gap junction

direct channel between epithelial cells

Desmosomes

structural reinforcement in areas that stretch

Hemidesmosomes

attach epithelial cells to the basement membrane

Cilia

hairlike projections that allow for movement

Microvilli

increase surface area

Connective tissue

A body tissue that provides support for the body and connects all of its parts

Components of connective tissue

fibers and cells

Fibers in connective tissue

help provide structure and support

-- collagen fibers = strong thick hairs

-- elastic fibers = thin and stretchable

-- reticular fibers = delicate and net like

Cells in connective tissue are

named by function

*** -blast cells : immature building blocks

*** -cyte cells : mature and only consisting of the existing matrix

Fibroblasts

fiber building cells in connective tissue

Chondrocytes

mature cartilage cells

Osteocytes

mature bone cells

Erythrocytes and Leukocytes

mature blood cells

Functions of connective tissue

binding, support, protection, insulation, energy storage, and transport

Connective tissue proper

1) Loose

- Areolar

- Adipose

- Reticular

2) Dense

- Regular

- Irregular

- Elastic

areolar connective tissue

wraps and conditions organs in addition to retaining extracellular fluid

contain collagen, elastic, and reticular fibers

visible fibroblasts and leukocytes

found surrounding organs and below the epilelium

Adipose tissue

fatty tissue composed of adipocytes located in the abdominal cavity, under the skin, and breasts.

function as lipid storage, protection, and insulation

have nucleus on the side of the cell and are filled with a lipid droplet

Reticular tissue

containing reticular fibers which contain leukocytes and erythrocytes.

Located in the lymph nodes,, the spleen, liver, and bone marrow.

Functions to support blood cells and assists in filtration.

Regular Connective tissue

tendons, aponeurosis and ligaments

all parallel with fibroblasts squished between the fibers

allows for strong attachment for bones and muscles

withstands pulling in one direction

Irregular Connective Tissue

many collagen fibers arranged irregularly located in the reticular layer of dermis and capsules around joints and organs.

withstands pulling in many directions

Elastic Connective Tissue

elastic fibers that appear dark purple in color when stained located in walls of large arteries and walls of bronchial tubes in the lungs.

Allows for stretching and recoiling

Cartilage

tough and dense flexible membranes

- chondrocytes: sparsely distributed cells in the lacunae surrounded by perichondrium (dense irregular connective tissues)

*** avascular

Functions of cartillage

-- strong and flexible to protect joints

-- helps joint shape when moving

-- absorbs shock

hydraline cartilage

cells are chondrocytes, found in lacuna and are glass like.

Found in the fetal skeletons, some joints, and nose

Template for bone and support and reinforcement.

Elastic cartilage

contains elastic fibers

located in external ear and epiglottis

Maintain shape and felxibility

Fibrocartilage

thick visible collagen fibers

- stain blue

- chondrocytes stain pink

Located in the intervertebral discs on the spine, knee, and temporomandibular joint

Provide strong support and absorb shock

Compact bone

contains calcium phosphate and collagen

- osteocytes arranged in osteons called lamellae

- blood supply is the Haversian canal

Outside of the bone

Allows for support and protection, muscle attachment site, and calcium storage.

Spongy bone

has trabeculae ( little columns that distribute force )

Found beneath compact bone

functions to form erythrocytes and store fat

Blood Connective Tissue

extracellular matrix of blood is plasma

-- plasma surrounds and supports cells

-- containing blood clotting proteins, nutrience, clotting proteins, hormones, gases, and water

Platelets: initiate clotting

Erythrocytes: O2 and CO2 transport

Leukocytes: immunity

Nervous tissue

detects and responds to stimuli

Neurons send impulses and glial cells help the neurons

Membranes are composed of....

epithelial tissue + connective tissue

Mucus membranes

linings of natural body openings, such as mouth, nose, rectum, genitals and eyes

Serous membranes

on organs in the ventral cavities

Cutaneous membranes

the skin

Skeletal muscle

- striated

- attached to bones and allows for the movement of the secretion

- multinuclear

- unbranched

- activity is voluntary ( signal needs to be received from the brain )

Cardiac muscle

- striated

- on the heart and pumps blood

- 1 or 2 nuclei

- branched: intercalated discs form direct cytoplasmic connection end to end

- activity is involuntary ( signal does not need to be received from the brain )

Smooth muscle

- not stratified

- on hollow organs, blood vessels, etc...

- moves food, helps regulate blood pressure, etc...

- single nuclei

- unbranched

- activity is involuntary

The type of tissue that protects, insulates, and stores lipids is __________ connective tissue.

adipose tissue

Transitional epithelium is found lining which of the following?

urinary bladder

Glandular epithelium contains glands that secrete specialized materials. If the materials are secreted into the bloodstream, the gland is termed ________. If they are secreted out of the body or an organ via ducts, the gland is termed _____________.

1) Endocrine

2) Exocrine

The dominant thick strong fiber types found in dense connective tissue are _____ fibers.

collagen

This connective tissue that is mostly fibers with few cells, contains all three fiber types is:

areolar

Chondrocytes are to cartilage as osteocytes are to:

bone

Hematopoiesis in spongy bone means:

making red blood cells

What is the major component of plasma

water

Muscle tissue with no striation is....

smooth

The delicate, net-like framework of organs is made of the following type of connective tissue.

recticular

The two types of connective tissues whose living cells are found in in lacunae are:

cartilage and bone

Which kind of intercellular junctions would you find in transitional epithelium?

desmosome

Multinucleated cells are found in __________ muscle.

skeletal

What is a tissue?

a group of cells plus extracellular materials

The type of intercellular junctions that anchor epithelial cells to underlying connective tissue is

hemidesmosome

The type of epithelial tissue that is best for absorption and secretion is __________ epithelium

simple squamous epithelium

The type of tissue found on external surfaces and internal cavities is ____________.

epithelial

The type of intercellular junctions that prevents leaking between cells are ___________ junctions.

tight

The tough cartilage with thick collagen fibers found in the intervertebral discs, knee, and temporomandibular joint is

fibrocartilage

A major function of smooth muscle is to

move food

The tissue that always has an apical and a basal surface is __________ tissue.

epithelial

The extracellular matrix of bone contains:

calcium phosphate and collagen

Which of the following types of cells are part of the immune system?

leukocytes

Of the following types of epithelial tissue, which is most protective from abrasion?

stratified squamous epithelium

Whate type of cartilage is found in the epiglottis?

elastic cartilage

true or false: at least one type of cartilage is vascular

false -- cartilage is avascular

Epithelial tissue adapted for aborption and secretion will have what on their surface?

microvilli -- to increase surface area