Chapter 5 - Integumentary System

Question 1

What makes up the integumentary system?

Answer 1

Skin, hair, nails, and cutaneous glands

Question 2

What percentage of body weight does your skin make up?

Answer 2

7-15%

Question 3

What tissue types make up the integumentary system?

Answer 3

All 4

Question 4

What are the two primary regions of the skin? What is the region that is not part of the skin but often studied together?

Answer 4

1. epidermis
2. dermis
   Not skin - hypodermis

Question 5

What does the skin protect against?

Answer 5

Resists physical trauma and infection (keratin and desmosomes)
Bacterial invasion (sebum is acidic, dendritic cells phagocytize pathogens, outer layer is dead and dry)
UV Radiation

Question 6

How does the skin regulate water loss/absorption?

Answer 6

Keratinized cells control water entering/leaving the body

Insensible and sensible perspiration

Question 7

What is the difference between insensible and sensible perspiration?

Answer 7

Insensible is the release of water when not visibly sweating, sensible is visible sweat

Question 8

Why is the skin important in vitamin D production?

Answer 8

Vitamin D production is important in bone development and requires small amounts of UV light to produce

Question 9

How does the skin gather sensory information?

Answer 9

It’s the largest sensory organ. It senses tough, pressure, pain, and temperature and supply the CNS with information about external condictions

Question 10

How does the skin regulate body temperature?

Answer 10

Thermoreceptors
When body temp increases, blood vessels dilate and sweat glands become active
When body temp decreased, blood vessels constrict and piloerector muscles contract

Question 11

How does the skin help with communication?

Answer 11

Facial expression

Question 12

What are the 5 layers of the epidermis?

Answer 12

(starting at outermost layer)

1. Stratum corneum
2. Stratum lucidum
3. Stratum granulosum
4. Status spinosum
5. Stratum basale

Question 13

Which of the 5 layers of the epidermis is only found in thick skin?

Answer 13

Stratum lucidum

Question 14

What type of epithelium makes up the epidermis?

Answer 14

Keratinized stratified squamous epithelium

Question 15

Describe the epidermis (types of cells, vascular/avascular, nerves, etc)

Answer 15

Outer, thin region
Dead cells
Lacks blood vessels - diffusion of nutrients comes from basement membrane/CT
Few nerve endings - touch and pain

Question 16

What types of cells make up the epidermis?

Answer 16

1. stem cells
2. keratinocytes
3. melanocytes
4. tactile (merkel)
5. dendritic cells

Question 17

What are epidermal stem cells are where are they found?

Answer 17

Undifferentiated cells

Found int he stratum basale

Question 18

What do keratinocytes do?

Answer 18

Synthesize keratin (most of the epidermal cells)

Question 19

What do melanocytes do and where are they found?

Answer 19

Synthesize the pigment melanin (which shields DNA)

Found in the statue basale

Question 20

What do tactical/merkel cells do and where are they found?

Answer 20

Touch receptor cells associated with dermal nerve fibers

Found in the stratum basale

Question 21

What do dendritic cells do and where are they found?

Answer 21

Act as macrophages/immune cells
They originate in bone marrow
Found in the stratum spinosium and stratum granulosium

Question 22

What happens in the stratum basle?

Answer 22

Constant cell division

Question 23

What happens in the stratum spinosum

Answer 23

Some cell division, keratin produced

Cells flatten superficially

Question 24

What happens in the stratum granulosum?

Answer 24

lamellar bodies release lipid contents

Cornified cellular envelope develops (CE)

Question 25

What happens in the stratum lucidum?

Answer 25

Friction protection | Only in thick skin

Question 26

What happens in the stratum corneum?

Answer 26

Several layers of dead, keratinized cells Mechanical barrier Prevents desiccation

Question 27

What 3 factors determine skin color?

Answer 27

1. pigments 2. blood circulating through skin 3. thickness of stratum corneum

Question 28

What are the two types of skin pigments?

Answer 28

Melanin (determined by genetics, hormones, exposure to light) and Carotene (yellow pigment)

Question 29

Where do you find melanocytes?

Answer 29

S. basale and S. spinosum

Question 30

Do darker skinned people have more melanocytes?

Answer 30

No, each melanocyte just produces more melanin and the melanocytes are more spread out (basale -> corneum)

Question 31

What are local concentrations of melanin called?

Answer 31

Freckles and moles

Question 32

What are dermal papillae?

Answer 32

Upward, finger-like extensions of the dermis

Question 33

What are epidermal ridges?

Answer 33

Downward waves of epidermis | resists slippage, stress, and gets nutrients to epidermis

Question 34

What are lamellar corpuscles?

Answer 34

Allow for sensitivity to texture via vibration on friction ridges (finger prints)

Question 35

What are the two layers of the dermis? Which is deeper?

Answer 35

``` Papillary layer (superficial) Reticular layer (Deeper/thicker) ```

Question 36

What are some things found in the papillary layer?

Answer 36

Areolar tissue, tactile corpuscles, free nerve endings, blood vessels

Question 37

What are some things found in the reticular layer?

Answer 37

Dense irregular CT, tick bundles of collagen, sweat glands, nail roots, hair follicles, heat receptors, lamellar corpuscles

Question 38

Explain vasoconstriction/vasodilation and how it affects body temperature and blood pressure? Where are these vessels found?

Answer 38

Vasoconstriction - vessels narrow to reduces blood flow to skin, helps conserve heat Vasodilation - vessels hidden to increase blood flow to skin, help release heat Vessels are found in the dermis

Question 39

What is the hypodermis and what types of tissue make it up?

Answer 39

Subcutaneous layer, used for protection and binding | Tissues: areolar Ct, adipose tissue

Question 40

What types of cells make up the hair and nails?

Answer 40

Dead keratinized cells

Question 41

Where is hair NOT found on the body?

Answer 41

Palms, soles, lips, nipples, external repro. organs

Question 42

What are the functions of scalp hair?

Answer 42

retain heat | prevent sunburn and skin cancer

Question 43

What are the functions of eyebrow hair?

Answer 43

Accentuate facial expressions Reduce glare Funnel sweat out of eyes

Question 44

What are the functions of beard, pubic, and auxiliary hair?

Answer 44

Demonstrate maturity (puberty)

Question 45

What are the functions of guard hairs (vibrissae) hair?

Answer 45

Block foreign particles (nostrils, ears, eyes)

Question 46

What are the functions of trunk/limb hair?

Answer 46

Evolutionary remnants | Sensory

Question 47

What are the functions of eyelashes?

Answer 47

Shield eyes

Question 48

What determines hairiness?

Answer 48

Differences in texture and pigment of hair

Question 49

What are the three types of hair?

Answer 49

1. lanugo 2. vellus 3. terminal

Question 50

Describe lanugo hair and where/when is it found?

Answer 50

Fine, downy, unpigmented hair | Appears on the fetus (last 3 months of development)

Question 51

Describe vellus hair and where/when is it found?

Answer 51

Fine, pale hair that replaces lanugo by time of birth | All the hair of children except eyebrows, eye lashes, and scalp hair

Question 52

Describe terminal hair and where/when is it found?

Answer 52

Longer, coarser, and more heavily pigmented Eyebrows, eyelashes, and scape At puberty, terminal hair replaces vellus hair

Question 53

What are the 3 zones in the structure of the hair/follicle?

Answer 53

``` Hair bulb (swelling in dermis or hypodermis, only living hair cells) Hair root (remainder of follicle) Hair shaft (portion above skin surface) ```

Question 54

What are the 3 layers of hair (in a cross section)?

Answer 54

Medulla (core, absent from thin hair) Cortex (bulk) Cuticle (surface)

Question 55

What does the arrestor pili muscle do?

Answer 55

Contracts in response to stiuli | Smooth muscle attaching hair follicle to dermis, "goosebumps"

Question 56

What are the 3 stages of the hair cycle?

Answer 56

1. Anagen (growth stage, follicle grows deeper into dermis, hair cells make keratin and die) 2. Catagen (degeneration stage, mitosis in hair matrix stops, base of hair keratinizes) 3. telogen (resting stage, club hair falls out)

Question 57

What are the 5 types of skin glands? Which are the two subtypes of sweat glands?

Answer 57

Sudoriferous (sweat) - 1. merocrine/eccrine - 2. apocrine 3. Sebaceous 4. Ceruminous 5. mammary

Question 58

Describe merocrine/eccrine sweat glands and their job

Answer 58

``` Simple, coiled tubular Secrete directly to surface via duct Activate with increased temperature Job is to sweat and cool off body (merocrine secretion method) ```

Question 59

Describe apocrine sweat glands and their job

Answer 59

``` Simple, coiled tubular Secrete into hair follicles Activate at puberty, produce pheromones Produce body odor (merocrine secretion method) ```

Question 60

Describe sebaceous glands and their job

Answer 60

Associated with hair follicles Secrete sebum (oily substance) (holocrine secretion method)

Question 61

Describe ceruminous glands and their job

Answer 61

Produce cerumen (ear wax) Job is to make eardrum more pliable, help with waterproofing, antibacterial, blocks foreign particles Modified apocrine sweat glands

Question 62

Describe mammary glands and their job

Answer 62

Produce milk Develop during pregnancy and lactation (apocrine secretion method)