A&P unit 4 flashcards

what is epithelial tissue?

• Filteraton

• Absoprtion

• Protection

• Secretion

• A type of tissue that lines/forms a divider between our body and our environment

What three structures to all epithelial tissues share?

• free surface

• basal layer

• basement membrane

• → All of these tissues are avascular

How do simple and stratified epithelial tissues differ?

Simple has one layer of cells, while stratified has multiple

What are the 3 types of simple epithelial tissue?

1. simple squamous

2. simple cuboidal

3. simple columnar

What are the characteristics of simple squamous tissue?

• single, flat layer of cells that is thin and permeable.

• location: blood vessels and lung tissues

• function: rapid diffusion of materials

• “simple squamous spreads (diffuses)”.

What are the characteristics of simple cuboidal tissue?

• A single layer of cube-shaped cells

• function: secretion and absorption

• location: kidney tissues

• “A Rubik’s cube absorbs your thoughts.”

What are the characteristics of simple columnar tissue?

• single layer of tall, closely packed cells

• ^ may have cilia or goblet cells (secretes mucus)

• function: secretion of mucus for protection & absorption of substances

• location: lining of digestive tract

• “when you cough (columnar) mucus comes up”.

What are the three types of stratified epithelial tissue?

1. stratified squamous

2. stratified cuboidal

3. stratified columnar

Describe stratified squamous tissue:

• Thick layers protect the underlying layers

• location: epidermal layers of the skin

Describe stratified cuboidal tissue:

• more than one layer of cuboidal cells

• very rare in body

• location: salivary and mammary glands

Describe stratified columnar tissue:

• free surface is lined with columnar cells

• rare in the body

• location: larynx and male urethra

what is pseudo-stratified epithelium?

• Cell nuclei are found at different levels, so it appears stratified, but it is not.

• Function: secretion and absorption

• Location: upper respiratory tract

What is transitional epithelium?

• the free surface cells vary in appearance based on the stretching of the tissue

• location: found in the urinary bladder lining

What is the glandular epithelium?

• a group of cells that secrete a fluid substance

• ^ classified in two ways:

• 1. complexity

• 2. exocrine/endocrine

exocrine gland:

secretes substances outward through a duct (ex: sweat glands)

endocrine gland:

ductless glands that secrete hormones through the bloodstream (ex: thyroid gland), they are packed tightly together with capillaries running through glandular tissue

→ cells use exocytosis

What are the types of exocrine glands?

• Holocrine: cell rupture and spills products into a duct

• Apocrine: a portion of the cell pinches off with the secreted products

• Merocrine: cells excrete the products

What are the types of connective tissues?

connective tissue proper, cartilage, bone, and blood.

What are the functions/characteristics of connective tissues?

• provide support and bind other tissues together

• provide insulation and protection for other tissue

• Some can transport substances

• All are formed from one stem cell

• vary in their degree of vascularity

• All are mostly composed of extracellular matrix

What are the 3 types of loose connective tissue?

• Reticular: contains reticular fibers, which create a stiff framework to support other cells

• Areolar: mostly open space, holds water and salts, found in the epithelium under other organs

• Adipose: composed of fat cells, large vacuoles that contain fat/oil, insulates and warms the body, and provides nutrients to other cells

What are the 3 types of dense connective tissue (DERMIS):

• Regular: collagen fibers arranged in one direction, providing tensile strength like a rope found in tendons and ligaments.

• Irregular: collagen fibers are arranged in many directions, providing strength in those directions, found in capsules around organs

• Elastic: provides flexible cushioning, found between vertebrae and arteries

What are the 3 types of cartilage?

• Hyaline: glassy looking, firm ground substance with lacuna, few collagen fibers, found in the larynx, bridge of nose,  and ribs

• Fibrocartilage: contains lots of collagen, mostly running parallel, found in intervertebral spaces

• Elastic: highly flexible, more elastic fibers, found in outer ear and tip of nose

What are the characteristics of bone tissue?

• Osteocytes: secrete ground substances, fibers, collagen, and fluids.

• The ground substance eventually becomes calcified and hard

• 2 types are spongy and compact

What are the types of vascular tissue?

• mast cells: detects foreign substances, contains granules that secrete inflammatory chemicals

• macrophages: blob-like cells that engulf invading substances or organisms

• blood cells

What are the layers of the epidermis:

1. stratum corneum: layer of dead cells, 20-30 thick. keratinized cells protect the deeper layers (shed regularly)

2. stratum lucidum: a thin layer of translucent cells only found in the palms and soles

3. stratum granulosum: cells here begin to flatten and disintegrate

4. stratum spinosum: “spiny layer” named for the irregular shape of cells.

5. stratum basale: diving and pushing cells up into the next layer

How melanocytes protect the body?

• Melanin protects the skin from harmful UV rays

• When UV radiation mutates a cell’s DNA, it starts to divide uncontrollably.

What are the characteristics of the dermis?

• contains: nerves, blood vessels, sweat glands, and hair follicles

• papillary layer: loose connective tissue

• reticular layer: made of bundles of collagen fibers → arrangement causes lines of cleavage/tension

Why are lines of cleavage important?

• for surgeons

• cuts should be made parallel to the lines of cleavage for quicker healing + less formation of scar tissue

What are the characteristics of the hypodermis?

• subcutaneous layer

• composed of loose, fatty, connective tissue

• insulates and stores nutrients

What are the characteristics of the Sudoriferous glands?

1. sudoriferous: sweat glands

• Eccrine sweat glands are long tubes that open into pores on the surface of the skin

• Apocrine sweat glands contain all the original components of sweat

2. sebaceous: oil glands

• holocrine glands

• lubricates skin and hair + kills bacteria

Hair follicle parts:

← know parts

• the hair follicle is located in the dermis

• cells divide within a region of the follicle called the hair bulb

• ^ these are filled with keratin and pigments

• tiny arrector pili muscles attach to the hair shaft to make it stand

Nail parts:

Know + label ( proximal is underneath)

• protective and a good tool

• The nail matrix produces heavily keratinized cells

• protected on 3 sides from folds

• lunula: “little white moon”

• cuticle: a seal for the nail matrix

Shallow cut vs. Deep cut

1. shallow: affects only the epidermis, results in these cells to divide more rapidly to fill the gap

2. deep: reaching dermis or subcutaneous layer, blood vessels break → forming a clot

identify burns from first degree → third degree

1st: injures only the epidermis; redness, heat, inflammation, heals in 2 days

2nd: destroys epidermis and some dermis; blister, stem cells help regenerate, usually recovering completely with no scarring

3rd: destroys epidermis and dermis + extra structures; minimal healing from margins, often requires a skin graft (replacement)

What is the rule of nines?

• estimates the extent of the injured body surface

• divides the body’s surface into 9% or multiples of 9 

• ^ to estimate plans to replaces fluids, electrolytes, and skin can be figured.