COM 1 histology week 5

Question 1

Where is the sebaceous gland found + places its not

Answer 1

Throughout the dermis
Except pals and soles

Question 2

Explain the type of sebaceous gland

Answer 2

Branched acinar glands

Question 3

Where do the sebaceous glands open into

Answer 3

Upper part of the hair follicle

Question 4

What does the combination of hair follicle and sebaceous gland equal

Answer 4

Pilosebaceous unit

Question 5

What are sebaceous glands derived from

Answer 5

Stem cells in the bulge region of the follicle

Question 6

How do sebaceous glands release their products

Answer 6

Via holocrine

Question 7

Explain the cell types in sebaceous gland

Answer 7

-Basal cells which then proliferate and differentiate into sebocytes

Question 8

What do the cells in the sebacaous gland undergo and release

Answer 8

The sebocytes undergo autophagy, disintegrate and release lipid rich sebum

Question 9

What does sebum contain

Answer 9

Wax esters, squalene, cholesterol and triglycerides

Question 10

What is the 2 roles of sebum:
-What it maintaints
-Wat it has

Answer 10

It maintains stratum corneum and hair shaft
-Has mild antibacterial and antifungal effects

Question 11

When does sebum production increase

Answer 11

At puberty

Question 12

What is sebum production stimulated by

Answer 12

-Testosterone in males
-Ovarian and adrenal androgens in females

Question 13

What is Acne vulgaris

Answer 13

Inflammatory condition of the pilosebaceous unit

Question 14

What causes Acne vulgaris

Answer 14

• Excessive keratinizatoon whcih leads to duct blockage
  -Increased sebum production

Question 15

Name the bacteria involved in Acne vulgaris

Answer 15

• Propionibacterium acnes

Question 16

What does Acne vulgaris lead to

Answer 16

Local inflammation, neutrophil infiltration whcih leads to enlarged follicle

Question 17

What are sweat glands

Answer 17

Long epidermal invaginations in the dermis

Question 18

Name the 2 types of sweat glands indictae which is localised an widespread

Answer 18

-Eccrine sweat glands-widespread
-Apocrine sweat glands - localised to axilla

Question 19

Where are Eccrine sweat glands found throughout+ and where are they most numerous

Answer 19

• Throughout the skin
  Most numerous on soles of feet

Question 20

Wha does Eccrine sweat glands function in

Answer 20

They function in thermoregulation, excretion, and skin cooling

Question 21

Explain the structre of Eccrine sweat glands

Answer 21

-Coiled tube with 2 main parts :
-Secretory portion
-Duct portion

Question 22

What is the secretory portion of the eccrine sweat gland made out of

Answer 22

Stratified cuboidal epithelium

Question 23

Name the 3 cell types the secretory portion of the Eccrine sweat gland contains

Answer 23

• Clear cells
  Dark cells
  Myoepithelial cells

Question 24

Explain the 3 types of cells in the secretory portion:
- 1. Where is it + What does it transport and produce
2. What does it contain+ what does it use and to release what
3.How does it work

Answer 24

Clear cells:
-On basal lamina
-Transport water and electrolytes to produce sweat
Dark cells:
-Contain eosinophilic granules
-uses merocrine secretion to release glycoproteins
Myoepithrlial cells :
- Contract to push sweat into the duct

Question 25

Explain the duct portion of the eccrine sweat gland: -Characteristics -What its lined by -Function( what does it reabsorb+ why)

Answer 25

- Darker-staining, smaller lumen -Lined by 2 layers of acidophilic cells with NA+/k+-ATPase pumps -It reabsorbs NA+ to prevent salt loss

Question 26

Give another role of the Duct portion of the eccrine gland - what does it help with

Answer 26

Helps excrete nitogenous waste and salts

Question 27

Where are apocrine sweat glands found

Answer 27

In axillary and perineal areas

Question 28

When do apocrine sweat glands become functionao

Answer 28

After puberty

Question 29

Explain the structure of the apocrine sweat glands :-lumen -lined by

Answer 29

Larger lumen then eccrine glands -Lined by simple epithelium with : - Eosinophilic secretory cells -Myoepithelial cells

Question 30

What do the ducts of apocrine glands open into+ what do secretions mix with

Answer 30

Hair follicles+ secretions mix with sebum

Question 31

Explain the secretions of the ducts in apocrine glands: -What they are like inititlay then later -What they may act as

Answer 31

- Initialy odorless but bacteria causes body odor -May act as vestigial sex pheromones in humnas

Question 32

What do adrenerguc nerves stimulate

Answer 32

Apocrine glands

Question 33

What does cholonergic nerves stimulate

Answer 33

eccrine glands

Question 34

Why does skin have a strong repair capacity

Answer 34

Due to its exposure to damage

Question 35

What does wound healing involve+ what does the duration of wound healing depend o

Answer 35

Several overlapping stages -Depends on wound size

Question 36

Name the 4 stages of wound healing

Answer 36

-Inflammatory phase - first 2-3 days -Epithelialization- begins before inflammation ends -Granulation tissue formation -Remodeling and scar formation

Question 37

Explain what happens in the inflammatory phase(first 2-3)days (4)

Answer 37

Blood coagulation at the wound site -Plataelets release grwoth factors and chemokines -Neutrohils and macrophages migrate to the site The immune cells remove bacteria and debri

Question 38

Explain wht happens in the epithelialization phase- starts before inflammation ends: -wHat happens to the basal epirdermal cells : -wht do they loose+ do -What is migration and growth stimulayed by

Answer 38

Basal epidermal cells: -Loose desmosomes and hemidesmomes -Then they migrate laterally under the blood clot -Migration and growt stimulaed by: -Growth factors -Matrix metalloproteinases(MMPs)

Question 39

Explain granular tissue formation: -What forms granulation tissue -What does granulation tissue replace

Answer 39

Proliferating fibroblats + new capillares from granulation tissue -Granulation tissue replaces the blood clot

Question 40

Explain the remodelling and scar formation: -Wjat does the epidermis restablis -What is not restored -What is remodelled and how + what does this lead to

Answer 40

-Epidermis reestablishes continuity(skin closes) -Hair and gand regeneration is not restored -Granulation tissue os remodeled : More organzied vasculature forms + collagen and fibroblasts remain abundant -Leads to scar tissue formation at wound site