Tissues

What is epithelial tissue?

a sheet of cells that covers a body surface or lines a body cavity

The _____ is not attached to surrounding tissue and is exposed to either the outside of the body or the cavity of an internal organ.

apical surface or "free" surface

The _______ is attached to the underlying connective tissue.

basal surface or "fixed" surface

Epithelia exhibit _________ due to their two surfaces.

apical-basal polarity

What are myofilaments?

contractile proteins (actin and myosin) in muscle cells

Describe skeletal muscle tissue.

long, cylindrical, multinucleate cells with obvious striations

What is the function of skeletal muscle tissue?

voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control

What is the location of skeletal muscle?

attached to bones or skin

Describe cardiac muscle tissue.

Branching, striated, uninucleate cells interlocking at intercalated discs

What is the function of cardiac muscle tissue?

as it contracts, it propels blood into the circulation; involuntary control

Where is cardiac muscle located?

within the heart wall and septum

Describe smooth muscle tissue.

cells are spindle shaped with central nuclei; no striations; cells are arrange closely to form sheets

What is the function of smooth muscle tissue?

propel substances or objects (foodstuffs, urine, a baby) along internal passageways; involuntary control.

Where is smooth muscle tissue located?

mostly in the walls of hollow organs

Define peristalsis

wavelike contractions of the smooth muscle of the digestive tract that force food through the tube and waste toward the anus

What are neurons?

highly specialized nerve cells that generate and conduct nerve impulses

What are glial / neuroglial cells?

non-conducting cells that support, insulate, and protect neurons

What is skin?

cutaneous membrane

layers of the cutaneous membrane

- epidermis (keratinized stratified squamous epithelium)
- dermis (connective tissue)

Membranes that line all body cavities that open to the outside of the body (hollow organs of digestive, respiratory, and urogenital tracts)

mucous membrane / mucosae

The epithelial sheet that lies directly over a layer of area connective tissue is called the _________.

lamina propria

Describe simple squamous epithelium:

single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; the simplest of the epithelia

What is the function of simple squamous epithelium?

- allows for quick and easy exchange - filtration and diffusion of gases

Where is simple squamous epithelium found?

**where protection isn't important
- alveoli and kidney glomeruli
- lymphatic vessels
- mesothelium: lines the ventral cavity wall (serous membranes)
- endothelium that lines the cardiovascular system

Describe simple cuboidal epithelium.

single layer of cubelike cells with large, spherical central nuclei

What is the function of simple cuboidal epithelium?

- secretion and absorption

Where is simple cuboidal epithelium found?

- lines tubules and small ducts of glands (kidney, pancreas, salivary glands and ovary)

Describe simple columnar epithelium.

a single layer of tall cells with oval-shaped nuclei; some bear cilia, others may contain microvilli

What is the purpose of microvilli?

increase surface area for absorption

What is the purpose of cilia?

propulsion and motility

What is the function of simple columnar epithelium?

- absorption
- secretion of mucus, enzymes, and other substances
- ciliated type propels mucus or reproductive cells by ciliary action

Where is simple columnar epithelium found?

- digestive tract (stomach, colon, galbladder)
- reproductive tract (fallopian tubes and some regions of the uterus)

Describe pseudostratified columnar epithelium

single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; cells rest on basement membrane; may contain mucus-secreting goblet cells and bear cilia

What is the function of pseudo stratified columnar epithelium?

- secretions protect, moisten and lubricate the throat and respiratory tract

Where is pseudo stratified columnar epithelium located?

- respiratory tract (bronchi, bronchioles, larynx, trachea)

Describe stratified squamous epithelium

thick membrane composed of several cell layers; basal cells are cuboidal or columnar and metabolically active; surface cells are flattened (squamous); in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitos

What is the function of stratified squamous epithelium?

protects underlying tissues in areas subject to abrasion

Where is stratified squamous epithelium found?

- esophagus, mouth, and vagina (non-keratinized)
- epidermis of the skin (keratinized

Describe transitional epithelium.

resembles both stratified squamous and stratified cuboidal: basal cells are cuboidal or columnar, on the surface cells are dome shaped or squamouslike

What is the function of transitional epithelium?

stretch to permit distention

Where is transitional epithelium found?

- urinary bladder
- ureters and part of urethra

mesothelia lining pleural, pericardial, and peritoneal cavities

simple squamous

lines the lungs and inner surface of the chest

pleura

covers entire abdominal wall and envelopes the organs in abdomen

peritoneum

surrounds the heart and large vessels entering and leaving the heart

pericardium

the simple squamous epithelium lining the heart, blood vessels, and lymphatic vessels

endothelium

Capillaries consist exclusively of _________.

endothelium

the simple squamous epithelium lining ventral body cavities and covering its organs

mesothelium (serosae)

If simple squamous epithelium is the most delicate, why does it make up the mesothelium lining the pleural, pericardial, and peritoneal cavities?

it reduces friction, allows for easy filtration, exchange, and diffusion of gases

what is serosae?

serous membrane

lines glomerular capsules (Bowman's capsule)

simple squamous

lines alveoli

simple squamous

Lines lymphatic vessels

simple squamous

lines vagina

nonkeratinized stratified squamous

lines esophagus

nonkeratinized stratified squamous

lines mouth

nonkeratinized stratified squamous

forms the epidermis of the skin

keratinized stratified squamous

forms the walls of (the smaller) kidney tubules

simple cuboidal

forms the walls of ducts and secretory portions of small glands (pancreas, salivary glands)

simple cuboidal

forms the surface of the ovary

simple cuboidal

Lines most of the digestive tract (stomach to rectum and gallbladder)

non-ciliated simple columnar

lines uterine tubes and some regions of the uterus

ciliated simple columnar

what is the function of ciliated simple columnar epithelium?

to propel mucus or reproductive cells by ciliary action

lines the nasal cavity

pseudo-stratified ciliated columnar epithelium

lines the trachea and bronchi

pseudo-stratified ciliated columnar epithelium

the three primary germ layers of embryonic development

ectoderm, mesoderm, and endoderm

the 4 main classes of connective tissue

connective tissue proper, cartilage, bone, blood

All connective tissue arise from ________.

mesenchyme

What is mesenchyme?

embryonic tissue that forms connective tissue, blood, and smooth muscles

immature, undifferentiated stem cells

-blasts

mature cells

-cytes

connective tissue proper cells

fibroblasts, fibrocytes, adipocytes, leukocytes, macrophages, and mast cells

Fibroblasts in connective tissue proper become ________.

fibrocytes

What are adipocytes?

fat cells - cells that store energy as fat

What are leukocytes?

white blood cells

What are mast cells?

cells that initiate local inflammatory responses against foreign microorganisms

Mast cells contain what chemicals?

heparin, histamine, and proteases

What is heparin?

an anticoagulant

What does histamine do?

promotes inflammation

What are proteases?

enzymes that break down proteins

all mature connective tissues except for bone cartilage and blood are...

connective tissue proper

two subclasses of connective tissue proper

loose connective tissue and dense connective tissue

loose connective tissue

areolar, adipose, reticular

dense connective tissue

dense regular, dense irregular, elastic

Fibroblasts are the predominant cell type in ________ connective tissue.

areolar

What is the function of areolar connective tissue?

- absorbs fluids during inflammation
- binds body parts together, but allows some free movement

Where is areolar connective tissue located?

it surrounds glands, nerves and small vessels. it also forms the basement membrane in subcutaneous tissue.

In reticular connective tissue, the _______ forms the internal supportive framework of lymphoid organs.

stroma

What is the function of reticular connective tissue?

support

Where is reticular connective tissue found?

liver, spleen, bone marrow, and lymph nodes

_________ connective tissue contains lipids and cholesterol.

Adipose

What is the function of adipose tissue?

protects, insulates, and reserves energy fuel

What is brown fat?

adipose cells that contain abundant mitochondria that use the lipid fuels to generate heat

cartilage cells

chondrocytes

Chondrocytes live in small chambers called ________.

lacunae

the most abundant cartilage in the body

hyaline cartilage

Where is hyaline cartilage located?

articular, nasal and costal cartilage, trachea and larynx

What cartilage has a great tolerance to repetitive bending?

elastic cartilage

Where is elastic cartilage located?

external ear, epiglottis

Fibrocartilage is mostly made up of what?

collagen fibers

Fibrocartilage is the ________ cartilage.

strongest

Where is fibrocartilage located?

intervertebral discs, pubic symphysis, menisci

intervertebral discs

fibrocartilage

pubic symphysis

fibrocartilage

menisci of the knee

fibrocartilage

articular ends of bones

hyaline cartilage

nasal cartilage

hyaline cartilage

costal cartilage

hyaline cartilage

tracheal ring cartilages and cartilage of the larynx

hyaline cartilage

external ear

elastic cartilage

epiglottis

elastic cartilage

tendons

dense regular

ligaments

dense regular

Aponeurosis

dense regular

fascia of the dermis of skin

dense irregular

fibrous organ capsules

dense irregular

joint capsules

dense irregular

periosteum, perineurium, perimysium, and pericardium

dense irregular

heart valves

dense irregular

What is the function of fibrous (dense) connective tissue?

resists tension

Where is dense regular connective tissue found?

tendons, ligaments, aponeuroses

Where is dense irregular connective tissue found?

- fascia of the dermis of skin
- fibrous organ capsules
- joint capsules
- periosteum
- perineurium
- perimysium
- pericardium
- heart valves

Dense irregular CT contains more _________ than dense regular CT.

collagen

What is the jelly-like embryonic connective tissue of the umbilical cord?

Wharton's jelly

What type of membrane consists of epithelium and connective tissue, and lines body cavities open to the exterior?

mucous membrane

What type of membrane lines the thoracic walls and covers the lungs, and what is it called?

serous membrane called pleurae

What is pathology?

scientific study of changes in organs and tissues produced by disease

What is pus?

A collection of tissue fluid, bacteria, dead and dying tissue cells, white blood cells and macrophages in an inflamed area.

What is scurvy?

a nutritional deficiency caused by lack of adequate vitamin C needed to synthesize collagen

What are the signs and symptoms of scurvy?

blood vessel disruption, delay in wound healing, weakness of scar tissue, and loosening of teeth

What is VAC (vacuum-assisted closure)?

innovative healing process for open-skin wounds and skin ulcers; involves covering the wound with a special sponge, and then applying suction through the sponge

What is the outcome of skin stretching using VAC?

fibroblasts in the wound form more collagen tissue and new blood vessels proliferate, bringing more blood into the injured area, which also promotes healing

What is an adenoma?

any neoplasm of glandular epithelium, benign or malignant

What is the specific name for a malignant adenoma?

adenocarcinoma

What is Marfan's syndrome?

genetic disorder that affects the body's connective tissue

What is keloid?

an abnormal hyperplastic proliferation of scar tissue usually due to surgeries or trauma

What are adhesions?

abnormal joining of tissues

What is a biopsy?

surgically removing a tissue sample and examining it microscopically

What is blood plasma?

nonliving fluid matrix of blood

What is dysplasia?

any abnormal change or development; as in the shape and size of cells

What is anaplasia?

reversion of cells to a more primitive or less differentiated state

the replacement of destroyed tissue with the same tissue

regeneration

the replacement of destroyed tissue with fibrous connective "scar" tissue

fibrosis

What are the three main steps of tissue repair?

inflammation, organization, and permanent repair via regeneration and fibrosis

Why is blood considered a connective tissue?

it develops from mesenchyme and consists of blood cells surrounded by a nonliving fluid called blood plasma