Anatomy and Physiology: Membranes and Integumentary System

What are the 4 types of membranes?

• mucous (mucosa)

• serous

• cutaneous

• synovial

Where are mucosa membranes found?

mucosa membranes line compartments that are open to the external environment

In what organ systems are mucosa membranes found?

digestive, respiratory, urinary, and reproductive tracts

What are the functions of mucous membranes?

• absorption

• protects

• secretory functions

Where are serous membranes found?

they line body cavities that aren’t open to the external environment

What type of cells make up serous membranes

simple squamous epithelium (mesothelium)

What do serous membranes do?

they reduce friction between opposing surfaces

What are the parts of the serious membrane

• parietal (outer layer)

• visceral (inner layer; lines the outside of the organ)

• serous cavity (area in between parietal and visceral layers)

• serous fluid (fluid in the serous cavity)

Where are cutaneous membranes found?

• the SKIN (cutaneous membranes are just skin)

• the external surface of the body

What type of cells are cutaneous membranes made of?

keratinized stratified squamous epithelium

What is the function of cutaneous membranes?

• protecting internal organs

• preventing water loss

Where are synovial membranes found?

they line some joints of the body

What cells make up synovial membranes?

areolar CT (loose CT; squamous epithelial cells without basement membranes)

What is the function of synovial membranes?

• reduces friction between moving bone parts (synovial fluid)

• distributes nutrients to cartilage

What is integument?

SKIN

Where is the integumentary system?

covers the whole body

What organs and tissues make up the integumentary system?

• skin

• accessary tissues (nails, hair, sweat glands, sebaceous glands)

What are the functions of integument?

• protection

• preventing water loss

• temperature regulation

• sensory perception

• excretory organ

• formation of vitamin D

What are the layers of integument?

Epidermis and dermis (NOT SUBCUTANEOUS layer)

What are the layers of the epidermis in order from most superficial to deepest? (CLGSB)

• Stratum corneum

• Stratum lucidum

• Stratum granulosum

• Stratum spinosum

• Stratum basale

Which layers of the epidermis are living (not dead cells/keratinized)

• Stratum granulosum

• Stratum spinosum

• Stratum basale

• *Deepest 3 layers

Distinctive features of the stratum basale?

• one layer of cells

• melanocytes (pigment cells that absorb UV radiation)

• stem cells (create new epidermal cells)

Distinctive features of the stratum corneum?

layers and layers of dead/keratinized cells

What is the difference between thick skin and thin skin?

• Thin skin doesn’t have stratum lucidum (3rd layer of epidermis)

• thin skin is more sensitive than thick skin

Where is thin skin found?

• crook of the elbow

• back of the knee

• face (eyelids, checks, lips)

• genitals

• armpits

Where is the dermis found?

UNDER the epidermis

What type of cells make up the dermis?

dense (IRREGULAR) CT

What structures are found in the dermis?

• blood vessels

• sweat glands

• sebaceous gland

• hair follicles

• sensory nerve endings

• arrector pili muscles

What are the two subdivisions of the dermis?

• papillary layer (makes fingerprints!)

• reticular layer (has the “important structures mentioned)

What are the types of sensory nerves?

• free nerve endings

• Meissner’s corpuscles

• Pacinian Corpuscles

What is the function of Meissner’s corpuscles (sensory nerves)?

to sense LIGHT touch, temp, texture, slow vibrations

Where are Meissner’s corpuscles (sensory nerves) found?

in papillary layer of dermis(near basal layer of epidermis)

What is the function of Pacinian Corpuscles (sensory nerves)?

to sense deep pressure and fast vibrations

Where are Pacinian corpuscles (sensory nerves) found?

in reticular layer of dermis

What are the parts of a hair?

• hair bulb (base of the hair, largest part)

• root (length of hair from the bulb to the skin’s surface)

• shaft (length of hair exposed to the outside environment)

• arrector pili muscle

What is an arrector pili muscle?

a smooth muscle attached to the hair follicle that, when contracted, causes goosebumps

What steps make up the hair growth and replacement cycle?

1.) anagen phase

2.) catagen phase

3.) telogen phase

What happens during the anagen phase (hair growth cycle)

• first step of cycle

• active phase where cells grow and divide

• longest part of the cycle

What happens during the catagen phase (hair growth cycle)?

brief regression/ cell division stops

What happens during the telogen phase (hair growth cycle)?

• resting phase

• hair is shed

• cells of bulb start to regrow after 3-4 months (cycle repeats)

What are the types of glands?

• exocrine glands

• endocrine glands

What are exocrine glands?

CT lined with epithelial cells that secrete stuff (sweat, milk, saliva, etc)

What are endocrine glands?

specialized organs that secrete (specifically) hormones into the blood

What are examples of endocrine glands?

• thyroid

• pituitary

• testicles

• ovaries

What are the types of sweat glands?

• Merocrine

• Apocrine

What do merocrine glands do?

secrete sweat (99% water)

What do apocrine glands do and where are they located?

• location: axillary, pubic, and anal region

• function: secrete proteins and lipids (reactions with bacteria which leads to sweat)

What are sebaceous glands and what do they do?

• Exocrine glands in integument

• produce oily sebum (lubricant for skin and hair from hair follicles)

• sebum contributes to acne

What are the two ways tissue can be repaired?

• regeneration

• fibrosis

What is regeneration?

using cell division to replace dead/damaged cells to restore tissue function

What is fibrosis?

extensive damage requires scar tissue throughout CT during healing

What are the steps of wound healing?

1.) blood comes from wound (clotting proteins, WBC, antibodies gather at wound)

2.) blood clot forms (prevents infection; WBC clean wound)

3.) Damaged blood vessels regrow (fibroblasts produce new collagen fibers, macrophaes remove clot)

4.) epithelium regenerates from cell division (more CT replaced by fibrosis, scab forms)

What is fibrosis?

process that puts a thicker layer of CT back in the place of a wound. Can impair function if a lot of CT is needed to repair wound.

What is basal cell carcinoma?

• most frequent type of skin cancer

• in stratum basale (deepest layer of epidermis)

• slow growing; metastasis rare

• usually from sun exposure

What is a squamous cell carcinoma?

• originates from stratum spinosum

• rough malignant nodule

• can metastasize (surgical removal, chemo sometimes)

• from sun damage or burns

What is a malignant melanoma?

• most deadly

• from melanocytes, preexisting mole

• high risk of metastasis

• sun exposure

ABCDE rule of melanoma vs. mole

A - asymmetry (moles are symmetrical)

B - boarder (moles have even boarders)

C - color (moles are one color)

D - diameter (moles are less than .25” diameter)

E - evolution (moles don’t change in size or shape quickly)