Chapter 5 - Integumentary System

Question 1

Function of the Integumentary System

Answer 1

A. Protection
B. Body temperature regulation
C. Sensation – function in sensing temperature, touch and pain (meissners corpuscles and pacinian corpuscles – receptors in receiving sensation)
D. Vitamin D synthesis and chemical conversion – this is where D3 is formed by sunlight though the skin
E. Blood reservoir – dermal layer has a good amount of vascular supply contains about 5% of bodies blood
F. Excretion – ammonia, uriea, water, and salt from the skin

Question 2

Epidermis

Answer 2

Superficial region; protective shield of the body and composed of epithelia tissue
A. Tissue type – keratinized stratified squamous epithelium
B. Vascularity – a vascular

Question 3

Epidermal Cells: Keratinocytes

Answer 3

Most numerous cells
A. Function – produces fibrous protein keratin which helps gives the epidermis protective property
B. Location – arise in the deepest part in the epidermal layer, in the stratum basale; they are pushed up as they grow.

Question 4

Epidermal Cells: Melanocytes

Answer 4

Spider shaped cells
A. Function – produce melinion (pigment-color)
B. Location – found in the deepest layer of the epidermis

Question 5

Epidermal Cells: Langerhans’ Cells

Answer 5

AkA epidermal dendritic cells and they are star shaped
A. Function – ingest foreign substances and are key activators of the immune system in that region
B. Location – arise from bone marrow and migrate to the stratum basale and make their way to the stratum spinosum.

Question 6

Epidermal Cells - Merkel Cells

Answer 6

Tactile cells – shaped like a spiky hemisphere
A. Function – behave as sensory receptors for touch, each tactile cells is associated with a disc like nerve ending and having the combination of the two this is called tactile Merkel discs.
B. Location – epidermal dermal junction, which is in the stratum basale

Question 7

Epidermal Layers

Answer 7

All made of stratified squamous

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Question 8

Epidermal Layers: Stratum Basale

Answer 8

Germinating layer, deepest layer and it is attached to the dermis
A. Cells – single role of stem cells, melanocytes, merkel (tactile cells)
B. Function – regenerate new basal cells

Question 9

Epidermal Layers: Stratum Spinosum

Answer 9

Known as the prickly layer and is several layers thick
A. Cells – keratinocyctes, langerhans cells
B. Function – contains thick bundles of intermediate fulminates made of prekeratin

Question 10

Epidermal Layers: Stratum Granulosum

Answer 10

About 3-5 layers
A. Cells – keratinocyctes
B. Function – keratinization – toughen keratinocyctes

Question 11

Epidermal Layers: Stratum Lucidum

Answer 11

Thin translucent band or layer above the stratum granulsosum, found in thick skin only
A. Cells – keratinocyctes – few rows of flat deat keratinocyctes
B. Function – has a gummy substances which clings to keratin filaments causing them to come together
C. Thick skin and thin skin
1. Thick skin – found in palms, finger tips, and soles of the feet has 5 layers
2. Thin skin – covers the rest of the body and consists of 4 layers (doesn’t have stratum lucidum)

Question 12

Epidermal Layers: Stratum Comeum

Answer 12

Outer most layer, has 20-30 cell layers thick 75% of epidermal thickness
A. Cells – dead keratinocyctes
B. Function – protect against abrasion, penetration and contains glycolipids which water proof this layer

Question 13

Dermis

Answer 13

Middle layer – second major skin region, its strong, flexible connective tissue (hide)

a. Vascularity – very vascular (lots of blood vessels)
b. Dermal layers
1. papillary layer
2. reticular layer

Question 14

Papillary Layer

Answer 14

Thin and superficial
A. Tissue type – areola connecter tissue with collagen elastic fibers and blood vessels
B. Additional structures -
1. Dermal papillae – peg like projections which contain capillary loops Messer’s copusculs and nerve endings
a. Dermal ridges – palms of hands and soles of feet
b. Epidermal ridges – comes together with the dermal ridges and are known as the friction ridges; friction ridges increase friction and enhance gripping ability and they are genetically determined and unique to everyone because when sweat pours open along the crests it leaves a finger print
2. Capillary loops – additional structures which are basically blood carrying vessels
3. Free nerve endings - pain receptors
4. Meissner’s corpuscles – tactile senses

Question 15

Reticular Layer

Answer 15

80% of demial thickness
A. Tissue type – irregularly arranged dense fibrous connective tissue
B. Additional structures
1. Cutaneous plexus – network of blood vessels which nourish this layer
2. Pacinian corpuscles – detect pressure changes and vibrations
3. Skin appendages – sweat glands, sebatious glands, the nail, hair root, and hair follicle receptors (root hair plexus)

Question 16

Sweat Glands

Answer 16

Distributed over the entire skin surface except nipples and external genitalia

Question 17

Eccrine Sweat Glands

Answer 17

AKA merocrine sweat glands, very numerous

a. Locations on body – palms, soles of feet and forehead
b. Locations within integument – in the dermis
c. Functions – secrete sweat which is 99% water, sodium, chloride, vitamin C, antibodies, metabolic waists, and some drugs. Also used for thermal regulation

Question 18

Apocrine Sweat Glands

Answer 18

Only 2000 in quantity, these glands are larger than eccrine sweat glands

a. Locations on body – axillary (arm pits) and anogenital areas
b. Locations within integument – deep dermis or hypodermis regions
c. Functions – unknown, but involved in thermal regulation and secrete sweat. The secretions are quite viscous and milky or yellowish in color, they are odorless but when they come in contact with bacteria then they take on an unpleasant smell.

Question 19

Ceruminous Glands

Answer 19

Modified apocrine glands

a. Locations on body – lining in external ear canal
b. Functions – the secretions mix with sebum which is secreted from sebaceous to create a stick and bitter substance which is known as cerumen

Question 20

Mammary Glands

Answer 20

Special sweat glands, are properly classified as part of the Integumentary system but also studied in female reproduction

a. Locations on body - breasts
b. Functions – secretions of milk

Question 21

Sebaceous Glands

Answer 21

Oil glands, greasy glands, simple branch – alveolar gland and develop from hair follicles and become active at puberty

1. Locations on body – found all over the body except in thick skin, few located on the truck and limbs, most are found on face, neck, and upper chest.
2. Locations within integument – next to a follicle or near a pour
3. Functions – secrete sabum

Question 22

Hair

Answer 22

1. Locations on body – entire surface excepts palms of hands, soles of feet, lips, nipples and portions of the external gentiles
2. Types of hair
   a. Vellus hair - pale and fine body hairs
   b. Terminal hair – more coarse, long hairs of eye brows, scalp, axillary, and pubic regions. Face and neck of males
3. Functions – alerts body of insects, guards scalp from physically trauma, helps from heat loss, and sun damage
4. Structure of hair – flexible strands which are produced of hair follicles and largely consists of dead keratinized cells

Question 23

Structure of Hair

Answer 23

a. Cell types
b. Two regions
i. Shaft - projects form the skin and it extends about half way down, portion that is embedded in skin; chief region of hair and this is where keratinizaiton is complete
ii. Root – the areas from the shaft to the bulb area, ongoing keratinizaiton
c. Three layers
i. Medulla – middle layer, only layer with soft keratin and this layer is absent in fine hairs
ii. Cortex – bulky layer, found surrounding the medulla, this is basically several layers of flattened cells
iii. Cuticle – single layer of cells that overlap like singles on a roof, most keratinized layer and it provides strength to the hair, hair conditioners smooth this layer

Question 24

Hair Follicles

Answer 24

a. Function – houses hair and hair bulb
b. Structure – wall
i. Locations within integument – folds down from the epidermis to the dermis, on the scalp it goes down to the hypodermis

Question 25

Hair Follicles: Wall

Answer 25

A. Connective tissue root sheath – derived from the dermis
B. Glassy membrane – thickened basement membrane
C. Epithelial root sheath – epidermal invagination
1. External epithelial root sheath – thins as they approach the hair bulb
2. Internal epithelial root sheath – thins as it approaches the hair bulb, that way there is only a single layer cover the papilla

Question 26

Arrector Pili

Answer 26

Bundle of smooth muscle cells that gives us goose bumps

Question 27

Nails

Answer 27

Scale like modifications of the epidermis that forms a clear protective covering on the distal dorsal fingers and toes

1. Locations on body – distal dorsal fingers and toes
2. Functions – behave as tools (pick up things and scratch and itch)

Question 28

Nails: Structures

Answer 28

a. Free edge – most distal part and this is the part that we trim
b. Body – found after free edge
c. Root – under the nail fold
d. Nail matrix – the part that’s responsible for nail growth
e. Cuticle – aka eponychium, hyponychium – under the free edge of the nail