Histology, Epithelial Tissue, Integumentary System

how does skin maintains homeostasis

regulates body temperature by sweating to decrease body temp and stick hair up to increase body temp

what are 2 functions of the integumentary system

1. create barrier between the environment and the body

2. absorbs nutrients

what are the 3 layers of integumentary system

• superficial to deep

epidermis

dermis

hypodermis

what is the function of epithelial tissue

covers body structures and glands that produce secretions

What is histology?

study of cells & tissues under the microscope

where is connective tissue found, and what is it’s function?

cells that are scattered in an extracellular matrix of fibers

• connects tissues and organs

what is muscle tissue?

consists of muscle fibers

• facilitates movement

• consists of excitable cells

what are the 3 types of muscle tissue

• skeletal

• cardiac

• smooth

what is nervous tissue?

consists of neuroglia (supporting cells) and neurons

• transmit nerve impulses throughout the body

What are 3 functions of epithelial tissue?

• secretions: glands

• protection: skin

• absorption: intestinal

how is epithelial tissue classified?

• cell shape

• number of layers

what is simple epithelial?

• what does it facilitate?

one cell layer

• one cell layer on the basement membrane

• absorption and filtration

what is stratified epithelial?

• what does it facilitate?

multiple cell layers

• deepest layer rests on the basement membrane

• protection of deeper layers from abrasion

what is simple squamous

• where is it found?

single layer of flattened cells

• heart

permeable: allowing small molecules to pass through quickly

• where gases can diffuse passively

what is simple cuboidal

• where is it found

single layer of square-shaped cells

• small duct glands

found wherever secretion and absorption functions

what is simple ciliated columnar

• where is it found

single layer if column-shaped cells

• lining of bronchi

what is simple non-ciliated columnar

• where is it found

single layer if column-shaped cells

• lining of digestive tract

what is pseudostratified columnar

• where is it found?

single layer of irregularly shaped columnar cells

• upper respiratory tract

stratified squamous

multiple layers of flattened cells

keratinized:

• epidermis

non-keratinized

• lining of mouth

found in areas of the body that experience high mechanical stress and friction

stratified cuboidal

multiple layers of square-shaped cells

• mammary gland ducts

in ducts exposed to mechanical stress and secretion demands

• protecting the walls of ducts

stratified columnar

multiple cell layers with basal cuboidal cells and apical columnar cells

• male urethra

found in areas requiring both

• protection

• secretion

transitional epithelium

multiple epithelial cells that can contract and expand

• lining of bladder

endocrine glands

secretes substances into the bloodstream

• hormones

exocrine glands

secretes substances onto skin, lumen of hollow organs, or ducts

• sweat

• tears

• oil on skin (sebum)

integumentary system: components

• hair

• skin

• nails

epidermis

• superficial to deep

stratum corneum

• stratum lucidum → in palms and soles of hands and feet

stratum granulosum

stratum spinosum

stratum basale

stratum corneum: corneocyte / dead keratinocyte

filled with keratin and surrounded by glycolipids

• forms protective barrier of skin

stratum granulosum

keratinocyte with granules

stratum basale

keratinocyte

• produce keratin, a fibrous protein protecting skin and cells

• most prominent cell in epidermis

melanocyte

produce the pigment melanin

• absorbs UV rays

• determines skin color

dermis: papillary layer

top layer

• made of areolar connective tissue

dermis: reticular layer

bottom layer

• made of sense irregular connective tissue

dermis: lamellar/pacinian corpuscle

transmit signals related to touch and vibration

dermis: tactile/meissner’s corpuscle

• detect light

• touch

• pressure

• vibration

free nerve endings

• detect pain

• temperature

• itch

• tickle