Anatomy & Physiology Exam 2 Shobnom Ferdous

Alopecia

thinning of the hair or baldness

Ceruminous glands

special exocrine glands found only in the dermis of the ear canals - their secretions combine with sebum and dead epithelial cells to form earwax (cerumen) - simple tubular coiled glands with ducts that lead to the skin surface

fingernails and toenails are made of:

stratum corneum cells packed with hard keratin

root

the remainder of the hair in the follicle

cuticle

thin, scaly cells that overlap each other. free edges directed upward - outermost coating of the hair shaft

exocrine glands functions:

- regulate body temperature by producing sweat - feed babies milk - cleansing - moistening and lubricating the eye to produce tears - help start digestion and lubricate the mouth to produce saliva

capillary hemangioma

- strawberry colored birthmarks appear in the skin as bright red to deep purple - nodules that are usually present at birth and disappear in childhood - however, their development may occur in adults

papillary layer

- superficial region of the dermis - composed of areolar connective tissue - contains dermal papillae - the epidermal ridges connect to the dermal papillae to increase the area of contact between the two layers and interlock them - each dermal papillae contain capillaries and sensory nerve endings; that continuously monitor touch on the surface of the epidermis - allows mobility of white blood cells - rich in small blood vessels

stretch marks (striae)

- tears in the collagen fibers caused by stretching of the skin

male pattern baldness

- the condition in which hair loss occurs from specific regions of the scalp - combination of genetic and hormonal influences - baldness allele is dominant in males, expressed only in high testosterone levels - testosterone causes terminal hair in scalp to be replaced by vellus hair

Stratum Basale

- the innermost layer of the epidermis - undergoes constant division of cells under mitosis - layer of cuboidal to low columnar keratinocytes in contact with the basement membrane - contains keratinocytes, melanocytes, tactile cells, and stem cells

carotene

-yellow-orange pigment acquired from various yellow-orange vegetables. - ex: carrots, corn, squash - accumulates in keratinocytes in stratum corneum and in subcutaneous fat - within the body, carotene is converted to vitamin A which plays a role in vision, reducing potentially dangerous molecules called free radicals that form during metabolic activity, and they improve immune cell number and activity

it takes ___________ months for a fingernail to grow from the root to the free edge

6

Two Kinds of sweat glands:

Merocrine (eccrine) and Apocrine

nonverbal communication

acne, birthmark, or scar

___________________ helps insulate the body by trapping body heat produce by the underlying muscles

adipose tissue

pheromones

an agent secreted by an individual that produces a change in the sexual or social behavior of another individual of the same species

what tissue makes up the hypodermis/subcutaneous layer?

areolar and adipose

what tissue makes up the dermis?

areolar and dense irregular connective tissue

smooth muscle (piloerector muscles)

associated with the hair follicles that help raise the hair when you have goosebumps

when blood rushes into vessels in the dermis, a person ____________ turning red, and when there is minimal blood in them, the skin turns ______________

blushes; blue

Eumelanin

brownish black pigment of skin

Hair is divisible into 3 zones:

bulb, root, shaft

Hair cycle

consists of 3 developmental stages: anagen, catagen, and telogen

cortex

constitutes bulk of the hair. consists of several layers of elongated keratinized cells - second layer of the hair shaft

medulla

core of loosely arranged cells and air spaces - inner most cavity of the hair shaft

keratin proteins found in keratinocytes are called ___________________

cytokeratins

collagen and elastic fibers ______________ with exposure to the sun and cause wrinkling

decrease

hirsutism

excessive or undesirable hairiness in areas that are not usually hairy

sudoriferous glands

exocrine glands found in the dermis of the skin and commonly known as sweat glands

sebaceous glands

exocrine glands found in the dermis of the skin that produce an oily secretion known as sebum - keeps skin and hair from becoming dry, brittle, and cracked - glands with ducts opening into hair follicle

nail root

extends proximally under overlying skin

lanugo

fine, downy, unpigmented hair that appears on the fetus in the last 3 months of development

an incision made _________________ to the cleavage line usually will remain closer to the cleavage line resulting in faster healing and less scarring

parallel

any cut ________________ to a cleavage line usually is pulled open as a result of the recoil resulting from cut elastic fibers. Which causes slow healing and increased scarring.

perpendicular

hair

pilus

Epidermal ridges

projections of the epidermis that interlock with the dermal papillae of the dermis. - think of an egg carton

Phenomelanin

reddish yellow pigment sulfur containing pigment

thermoregulation

regulation of body temperature by evaporation of fluid from the skin - thermo-receptors detect a change in the skin - vasoconstriction/vasodilation of blood vessels

telogen

resting stage; where the hair is shed

melanin

- accumulates around the nucleus of the keratinocytes and shields the nuclear DNA from ultraviolet radiation - gives people the color of their skin - tanning is a result of melanocytes producing melanin to block UV light from causing mutations in the DNA of keratinocytes (epidermis) and fibroblasts (dermis)

what layers of the skin are part of the integumentary system?

- epidermis - dermis - hypodermis

Accessory of Skin Organs

- nails, hair, sweat glands, sebaceous glands

fingernails grow ____________ than toenails

faster

vellus

fine, pale hair that replaces lanugo by time of birth - 2/3 of the hair in women - 1/10 of the hair in men - all hair of children except eyebrows, eyelashes, and hair of the scalp

nail plate

hard plate of the nail

the Skin and its accessory organs: nails, hair, oil glands, and sweat glands are collectively called the ______________________

integumentary system

three kinds of hair

lanugo, vellus, and terminal

The skin is the ________________ organ accounting for about _________________ of your total body weight

largest; 12-15%

terminal

longer, coarser, and usually more heavily pigmented - forms eyebrows, eyelashes, and hair of the scalp - after puberty, forms the axillary and pubic hairs - male facial hair and some of the hair on the trunk and limbs

The Epidermis

made up of keratinized stratified squamous epithelial cells formed in several layers

parts of the hair shaft

medulla, cortex, cuticle

3 pigments that make up the color of your skin?

melanin, carotene, hemoglobin

ALL PEOPLE HAVE THE SAME NUMBER OF ______________________. JUST DIFFERENT AMOUNTS OF ___________________

melanocytes; melanin

free edge

nail that overhangs the fingertip

vasoconstriction

narrowing of blood vessels; means less blood can flow through the dermal blood vessels, more blood is then transported through blood vessels deeper to the skin. - the shunting of the blood away from the surface and deeper toward the body is how our body conserves heat

shaft

the portion of the hair above the skin surface

it takes a toenail ____________________ months to grow from the root to the tip

12-18

cavernous hemangiomas

- "port-wine stains" involve larger dermal blood vessels and may last a lifetime

stratum granulosum

- 3-5 layers of flattened keratinocytes producing keratin - contains coarse dark staining keratin granules and lamellar granules - keratinization begins here - keratinocytes are still living in this layer but are starting to die - contains keratinocytes, epidermal dendritic cells

Tactile Cells

- Merkel cells - in basal layer of epidermis - touch receptors associated with nerve fibers - sensitive to touch; when compressed they release chemicals that stimulate sensory nerve endings, providing information about objects touching the skin

stratum lucidum

- ONLY ON THICK SKIN - 2-3 layers of a-nucleate, dead keratinocytes - thin translucent zone - keratinocytes are densely packed with eleidin - no nucleus or organelles - contains keratinocytes

keratin

- a protein that strengthens the epidermis considerably - tough and insoluble - can twist and intertwine to form helical intermediate filaments of the cytoskeleton - their structure in keratinocytes give skin strength and makes epidermis water resistant

hemangioma

- an anomaly that results in skin discoloration due to blood vessels that proliferate to form a benign tumor

Thin skin

- covers the rest of the body - contains hair follicles, sweat glands, and sebaceous glands - contains 4 of the 5 epidermal strata: (stratum corneum, stratum granulosum, stratum spinosum, stratum basale or germinativum)

The Hypodermis

- deep to the dermis - made of areolar and adipose tissue - subcutaneous layer - serves as flexible connection between the skin and underlying muscles and bones - fat storage area - contains elastin and collagen fibers; allow for skin to stretch and move independently

Reticular layer

- deepest layer of dermis; beneath the papillary - much thicker - surrounds and supports hair follicles, sebaceous glands, sweat glands, nerves, and blood vessels - made of dense irregular connective tissue - stretch marks (striae) are found here - tension lines/lines of cleavage

catagen

- degenerative stage - follicle undergoes involution - mitosis in the hair matrix ceases and sheath cells below the bulge die

Hypodermis functions

- energy reservoir - thermal insulation - padding - thicker in women - binds skin to underlying tissues - drugs introduced

collagen fibers in dermis:

- flexible and resistant to over stretching, and prevents skin from being torn - provide tensile strength

Keratinocytes

- great majority of epidermal cells - synthesize keratin

anagen

- growth stage where living cells of the hair bulb are rapidly growing, dividing, and transforming into hair - 90% of scalp follicles at any given time

melanin in the skin is determined by:

- heredity - light exposure

Epidermal dendritic (langerhans) cells

- immune cells that help fight infection in the epidermis - macrophages originating in bone marrow - located in stratum spinosum and stratum granulosum - their phagocytic activity initiates an immune response to protect the body against pathogens that have penetrated the superficial epidermis as well as epidermal cancer cells

function of cerumen

- keeps eardrum pliable - waterproofs the canal - kills bacteria - makes guard hairs of ear sticky to help block foreign particles from entering the auditory canal

The Dermis

- layer deep to the epidermis - contains primary collagen fibers, as well as elastic and reticular, contain dendritic cells - structures: blood vessels, sweat glands, sebaceous glands, hair follicles, smooth muscle tissue for arrector pili muscle, - 2 major regions: papillary and reticular

flexion lines

- lines on the flex or surface of the digits, palms, wrists, and elbows - marks site where skin folds during flexion of the joints

Melanocytes

- long branching process -produce and store the pigment melanin - scattered among the stratum basale - darker tones of the skin result from melanin produced by the melanocytes

elastic fibers in dermis:

- maintain normal skin tension but also stretch to allow movement of underlying muscles - stretch and recoil

Nevus

- mole - harmless aggregation of melanocytes - on a rare occasion, a nevus may become malignant typically as a response to UV exposure

merocrine glands

- most numerous sweat glands - simple tubular glands - watery precipitation that helps thermoregulation - myoepithelial cells

stratum corneum

- most superficial layer of epidermis - 20-30 layers of dead, flattened, a-nucleate skin cells - the "horny" layer - contains keratinocytes

stratum spinosum

- numerous desmosomes and cell shrinkage produces spiny appearance - consists of several layers of keratinocytes attached to neighboring desmosomes - These layers of keratinocytes produce pre-keratin filaments which cause cells to flatten - contains keratinocytes, epidermal dendritic cells

apocrine glands

- occur in groin, anal region, axilla, areola, bearded area in mature males - ducts lead to nearby hair follicles - produce sweat that is thicker, milkier, and contains fatty acids - develop at puberty - pheromones

Thick Skin

- on the palms and soles of feet; corresponding surfaces to fingers and toes - contains sweat glands - contains all 5 epidermal strata found here

hair is found almost everywhere on our body except:

- palms and soles - ventral and lateral surfaces of fingers and toes - distal segment of the finger - lips, nipples, and parts of genitals - number of hairs DOES NOT differ much from person to person or even between sexes - difference in appearance due to texture and pigmentation of the hair

Functions of the Skin

- protects underlying tissues from physical trauma, pathogen invasion, and water loss - helps regulate body temperature - synthesizes Vitamin D with the aid of ultraviolet radiation - contains sensory receptors, which helps us to be aware of our surroundings and to communicate through touch

hemoglobin

- protein found in blood cells that allow them to carry oxygen - Gives reddish-pink tint to skin

lines of cleavage

- the majority of the collagen and elastic fibers in the skin are oriented in parallel bundles at specific body locations - the alignment of fiber bundles within the dermis is a result of the direction of applied stress during routine movement - resists stress - important for surgical procedures

friction ridges

- these ridge patterns follow the contour of the skin - varying from small, conigal pegs, to complex arches and whorls - found on the fingers (fingerprint), palms, soles, and toes - these are formed from large folds and valleys of both the dermis and epidermis - they help to increase friction on contact; so that our hands can grasp items, so we don't slip when we walk barefoot, and provide flexibility to the skin and allow it to deform without being damaged - each individual has unique friction ridges

Nail function:

- they help human function (help humans dig, climb, scratch, grab, and more) - they guard against injury - they enhance the sensations (contain nerve endings that allow the body to process the volumes of information that it receives)

Stem cells

- undifferentiated cells that give rise to keratinocytes - in deepest layer of the epidermis

functions of hair

- warmth - sensation - protects against sunburn - pubic and axillary hair signify sexuality, maturity, and aid in transmission of sexual scents - guard hairs (vibrissae): guard nostrils and ear canals - eyelashes and eyebrows: nonverbal communication

Holocrine glands

- will release whole broken cells in your ductal system - these cells contain the reserve of substance that the gland will release - this secretion method requires frequent cell rotation and replacement

Freckles

- yellowish-brown spots that represent localized areas of increased melanocyte activity, NOT an increase in melanocyte number - aggregations of melanocytes - a freckles degree of pigmentation varies and it is dependent upon exposure and heredity

bulb

A swelling at the base where hair originates in dermis. only living hair cells are in or near the bulb

fatty adipose tissue in the hypodermis stores energy in the from of _______________

triglycerides

dermal papillae

upward fingerlike extensions of the dermis

nail body

visible attached part of nail

vasodilation

widening of blood vessels; relatively more blood is transported through the blood vessels when the dermal blood vessels vasodilate. In return, more blood is toward the superficial layers of the skin which allows the body to release excess heat - results in a pinkish/reddish hue of skin tone