General Anatomy - Integumentary System

Integumentary system

the organ system that protects body from damage, comprising the skin and its appendages (including hair, scales, and nails), glands and
nerve endings.

Integumentary system

It distinguishes, separates, protects and informs the animal with regard to its surroundings.

Integumentary system

Small-bodied invertebrates of aquatic or continually moist habitats respire using the outer layer (integument).

Integumentary exchange

This gas exchange system, where gases simply diffuse into and out of the intertitial fluid is called

Skin

Cutaneous membrane

skin

is the outer covering of the body

skin

In humans, it is the largest organ of the integumentary system made up of multiple layers of epithelial tissues and guards the underlying muscles

Protection

an anatomical barrier from pathogens and damage between the internal and external environment in bodily defense;

Sensation

contains a variety of nerve endings that react to heat and cold, touch, pressure, vibration, and tissue injury.

Heat regulation

skin contains a blood supply for greater than its requirements which allows precise control of heat loss by radiation, convection, conduction, and evaporation.

dilated blood vessels increase perfusion and heat loss while constricted
vessels greatly reduce blood flow in the skin and conserve heat.

Aesthetic and communication

others see our skin and can access our physical state and attractiveness

storage and synthesis

acts as a storage center for lipids and water, as well as means of synthesis of vitamin D

Excretion

sweat contains urea, however its concentration is 1/130th that of urine, hence excretion by sweating is at most a secondary function to temperature
regulation.

Absorption

Oxygen, nitrogen and carbon dioxide can diffuse into the epidermis in small amounts, some animals use their skin for their sole respiration organ.

In addition, medicine can be administered through the skin, by ointments or by means of
adhesive patch.

The skin is an important site of transport in many other organisms.

Water resistance

The skin acts as a water resistant barrier so essential nutrients aren't washed out of the body.

2, 4.5

skin: __ square meters, __ kg, constantly renewing

EPIDERMIS

the outer thinner portion which is composed of epithelial tissue

Keratinocytes

produce the protein keratin, that helps waterproof and protect the skin and underlying tissues.

keratinocytes

it is the major epidermal cell

Melanocytes

produces the pigment melanin a brown-black pigment that contributes to skin color and absorbs
ultraviolet (UV) light from the sun.

melanin

a brown-black pigment that contributes to skin color and absorbs ultraviolet (UV) light from the sun.

langerhans cell

interacts with white blood cells called helper-T cells in immune responses, and are easily damaged by UV radiation

Merkel cell

located on the deepest layer of epidermis (Stratum Basale). it make contact with the ending of a sensory neuron, and are thought to function in the sensation of touch

Stratum Corneum

consists of 25 to 30 rows of dead cells.
completely filled with keratin. Cells on this
layers are continuously shed and replaced
by cells from deeper strata.

It serves as
an effective barrier against light and heat
waves, bacteria and many chemicals.

Stratum Lucidum

usually not present on hairy skin, only the thick skin of the palm and soles has this layer.

It contains intermediate substance that was formed from keratohyalin which continually transformed to keratin.

Stratum Granulosum

develops keratohyalin - the precursor of
keratin.

Stratum Spinosum

tightly joins the lower and upper layer
together.

Stratum Basale

capable of continued cells division:
produces stem cells that produce and multiply melanocytes and keratinocytes which push up toward the surface and become part of the more superficial layer

DERMIS

composed of connective tissue containing collagen and elastic fibers. It varies in thickness, very thick in the palms and soles, and very thin in the eye lid and other parts of the body.

Fibroblasts

cell that produces collagen and elastic fibers.

Macrophages

cell of the lymphatic which fights bacteria.

adipocytes

cells that make up adepose tissue

papillary region

the upper dermal region. it is uneven and has fingerlike project projections from its superior surface called Dermal Papillae.

Dermal Papilae:

Indents the epidermis above Contains capillary loop which furnish nutrients to epidermis

dermal papillae

They are arranged in definite patterns on
the palm of the hands and soles of the
foot that form looped and whorled ridges
on the surface that increase friction and
enhance gripping ability of the finger and feet.

The pattern is genetically determined.

Reticular Layer

the deepest region. It contains blood vessels, sweat and oil glands, and deep pressure receptors

Melanin

located mostly in the epidermis

Carotene -

mostly in the dermis

Hemoglobin

in red blood cells within capillaries in the dermis.

HAIR

composed of columns of dead, keratinized cells welded together.

hair

primary function is protection, though limited.

eyelashes

protects the eyes from foreign particles

Hairs in nostrils

protects against inhaling insects and foreign particles.

Hairs on the head

guards the scalp from injury and the sun's rays, it also decreases heat loss.

5 million

approximately how many hairs in our body

vellus hair

fine, soft hair covering the limbs

terminal hair

thick, stiffer hair covering our head, eyebrows, beards, mustache

palm, soles, lips

are the only hairless areas of the body.

arrector pili muscle

causes goosebumps

100,000

how many hairs grow in our head

1.3cm

it is the length of the hairs that grows per month

100

adult loses about ____ hairs each day

male-pattern baldness

caused by reduced sex hormones in males

hair color

Due primarily to melanin in the hair cortex and medulla

dark colored hair

contains mostly true melanin

Blond and red hair

contain variants of melanin in which there is iron and more sulphur

Graying of hair

is the loss of pigment believed to be the result of a progressive decline of tyrosinase

tyrosinase

an enzyme necessary for the production of melanin.

Sebaceous (oil) Glands

produces sebum which moistens hairs and waterproofs the skin

sudoriferous glands

produces perspiration which carries small amount of wastes to the surface and assists in maintaining body temperature.

apocrine and eccrine sweat glands

2 types of sudoriferous glands

apocrine sweat glands

are largely distributed to the skin of the axilla, pubis and areola; their ducts open into hair follicles;

they begin to function at puberty they are stimulated during emotional stress and sexual excitement.

eccrine sweat glands

extensively distributed to the entire skin except for the margins of the lips, nail beds of the fingers and toes, most parts of the genitals, and ear drums

their ducts terminates at pores at the surface of the epidermis; most numerous in the palms and the soles;

eccrine sweat glands

function throughout life and produce a secretion that's more watery

apocrine sweat glands

produce a more viscous secretion

nails

Consists of a cornified nail plate (composed of modified stratum corneum) overlying a specialized region called the nail bed (composed of germinative layer)

nails

Functions mainly for protection of the upper part of the digits and aid in picking up objects and for scratching.

the root

Each nail consists of a proximal hidden part which is

the body

distal exposed part

eponychium (cuticle)

The root is covered by a curved fold of skin called the

lunula

The opaque, whitish, moon-shaped area is the found just beyond the cuticle.

hyponychium

Beneath the distal free-edge of the nail, the outer layers of the epidermis are thickened to form the ________ w/c is attached to the underside of the nail.

slanted

The follicle is usually _____, and the lower end of the root is expanded into a bulb w/c contains proliferating cells moving upward, causing the hair to grow.

reticular layer

contains combinations of collagen fibers that strengthens the skin

Ceruminous Glands

are modified sudoriferous glands that produce cerumen.

they are found in the external auditory meatus