Tissue Structure, Histology, Integument

Question 1

When do cells differentiate?

Answer 1

As the body divides from a fertilized egg

Question 2

What are the four kinds of tissue?

Answer 2

Epithelial, connective, muscle, neural

Question 3

What is the definition of an organ? What is the definition of a tissue?

Answer 3

Organ: two or more types of cells working together to perform specific functions
Tissue: a group of similar cells (and their products) working together to perform specific functions (includes the extracellular material and fluid directly around them)

Question 4

Epithelial locations

Answer 4

• covers exposed surfaces
• lines internal passageways and chambers
• forms secretory glands

Question 5

Connective tissue functions

Answer 5

• fills internal spaces
• provides structural support
• stores energy

Question 6

Muscle tissue functions

Answer 6

• contracts to produce movement

- includes skeletal muscle, cardiac muscle, and smooth muscle

Question 7

Nervous tissue functions

Answer 7

• conducts electrical impulses

- carries information

Question 8

Epithelial tissue functions

Answer 8

• provide physical protection
• controls permeability
• provides sensation
• produces specialized secretions

Question 9

What are the three types of epithelia structure?

Answer 9

1. Squamous
2. Cuboidal
3. Columnar

Question 10

What kind of tissue is a gland made of?

Answer 10

Epithelial

Question 11

What are the three kinds of glandular secretion?

Answer 11

1. Merocrine: released by exocytosis from secretory vesicles (e.g. mucin)
2. Apocrine: released by shedding apical part of cell and cytoplasm (e.g. milk production)
3. Holocene: released by the entire cell bursting, releasing contents (e.g. sebum production)

Question 12

What is connective tissue?

Answer 12

Definition: presence of extracellular protein fibres suspended in ground substance

Question 13

What are the three main types of connective tissue?

Answer 13

Proper, fluid, and supporting

Question 14

What are the two types of proper connective tissue?

Answer 14

Loose: areolar, adipose, reticular
Dense: regular, irregular, elastic

Question 15

What are the two types of supporting connective tissue?

Answer 15

Cartilage: hyaline, elastic, fibrocartilage

Bone

Question 16

What are some examples of extracellular fibres?

Answer 16

Elastin, collagen

Question 17

What do tissue membranes consist of?

Answer 17

Epithelial + underlying connective tissue

Question 18

What are the three layers of connective tissue?

Answer 18

Superficial, deep, subserous

Question 19

What is another name for skin?

Answer 19

Cutaneous membrane

Question 20

What makes up the integument? What is its primary function

Answer 20

Cutaneous membrane + accessory structures; first line of defence against the physical, chemical and biological environment

Question 21

What are the functions of the integument?

Answer 21

1. Barrier
2. Synthesize vitamin D
3. Sensory
4. Regulate body temp

Question 22

What is the hypodermis? Is it part of the integument?

Answer 22

Subcutaneous layer of tissue that is NOT part of the integument

Question 23

What does the epidermis consist of?

Answer 23

Stratified squamous epithelium:

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

Question 24

What layer of epidermis do cells lose their nuclei and organelles?

Answer 24

Granulosum

Question 25

What layer produces melanin and transfer them to keratinocytes?

Answer 25

Melanocytes within stratum basale via vesicle transportation

Question 26

How does the skin prevent UV light from damaging cells?

Answer 26

Melanin absorbs UV photons— enters a high energy state that is not reactive, so it can later release the energy as heat

Question 27

What does the dermis consist of?

Answer 27

• 2 layers of vascularized connective tissue, supporting cells for secondary functions

Question 28

What are the two layers of dermis?

Answer 28

Stratum papillare, stratum reticulare

Question 29

What is the the hypodermis often full of?

Answer 29

Adipocytes

Question 30

What are the mechanisms of tissue repair in epidermis and dermis?

Answer 30

Epidermis: quickly, through proliferation of basal cells (divisions without daughter cells specializing as keratinocytes)
Dermis: granulation tissue, a mixture of dividing mesenchymal cells, fibroblasts and new blood vessels

Question 31

What do myoepithelial cells do?

Answer 31

Epithelial derived cells with muscle like ability to contract, they surround glands

Question 32

What is the sensor, integrator and effector in temperature regulation?

Answer 32

Sensor: temperature receptors in the skin and brain
Integrator: brain
Effector: sweat glands and smooth muscle in the walls of blood vessels

Question 33

Where is vitamin D synthesized? What happens to it?

Answer 33

Stratum spinosum and basale

- vitamin D converts to calcitrol

Question 34

What is the trade off between melanin and vitamin D synthesis?

Answer 34

If some UV reaches basal layers, vitamin D is synthesized. If a LOT of UV reaches basal layers, cellular damage increases

Question 35

What are some effects of ageing on the integument?

Answer 35

• fewer melanocytes
• drier epidermis
• thinning epidermis
• decreased perspiration
• fewer active follicles
• diminished immune response
• thinning dermis
• reduced blood supply
• slower repair