Tissues & Integument

Question 0

Melanocytes

Answer 0

Secrete the brownish pigment melanin in granules that are taken up by neighbouring keratinocytes
They shield the nucleus and absorb UV to protect the DNA

Question 1

Stratum Basale

Answer 1

Deepest layer of the epidermis
Single layer of cuboidal stem cells
Undergo cell division and their daughter cells migrate upwards to replace dead keratinocytes in the upper layer of the epidermis
Also contain melanocytes

Question 2

Stratum Spinosum

Answer 2

Second-most deep layer of the epidermis
Keratinocytes produce tonofilaments, composed of an intermediate of keratin
Synthesis the lamellar granules

Question 3

Langerhans Cells

Answer 3

Immune cells that are scattered throughout the stratum spinosum
Have many cytoplasmic processes, known as dendrites, that detect antigens and present them to other immune cells

Question 4

Stratum Granulosum

Answer 4

Third-deep epidermis layer
Contains 3-5 layers of flattened keratinocytes that have undergone apoptosis
Produce the protein, keratohyalin, which converts the tonofilaments to keratin

Question 5

Stratum Lucidum

Answer 5

Found only on thick skin
Located on palms, soles and the palmar surfaces of the digits
Made up of 3-5 layers of dead keratinocytes that don’t have any nuclei
Appear transparent due to histological preparation

Question 6

Stratum Corneum

Answer 6

Most superficial layer of the epidermis
Contains 25+ sheets of dead squamous keratinocytes
Cells are full of keratin in order to provide a strong structural barrier

Question 7

Ion Channels

Answer 7

Allows a specific ion to move across the membrane

- e.g. sodium channel

Question 8

Receptor

Answer 8

Accepts a specific molecule and alter’s the cells function

- e.g. antidiuretic hormone binds in the kidney and changes the membrane’s permeability to water

Question 9

Transport: Passive

Answer 9

• Diffusion: lipid soluble substances cross the membrane from HIGH to low concentrations
• Carrier Facilitated: solute binds to the protein changing its shape to allow the substance to be released inside the cell
  e. g. facilitated glucose transport

Question 10

Transport: Active

Answer 10

• Primary Active Transport: uses ATP to move a substance against a concentration gradient
  e. g. sodium potassium ATPase
• Secondary Active Transport: uses the concentration gradient of one solute (e.g. Na) to help draw something else in (e.g. glucose)
  e. g. intestinal absorptive cells

Question 11

Linkers

Answer 11

• Link 2 cells together
• Links something on the cell’s outside to its inside
  e. g. linking cytoskeleton structure to structural proteins outside of the cell

Question 12

Enzymes

Answer 12

Catalyze reactions

e.g. lactase

Question 13

Cytoskeletal Elements:

Answer 13

1. Microfilaments
2. Intermediate Filaments
3. Microtubules

Question 14

Microfilaments

Answer 14

• Smallest
• Movement, Support
• Actin

Question 15

Intermediate Filaments

Answer 15

• Intermediate sized
• Strength
• Keratin

Question 16

Microtubules

Answer 16

• Largest

- Transportation (vesicles), DNA separation

Question 17

ECM

Answer 17

Non-cellular component present within all tissue. It fills the spaces in-between cells. Helps to bind and support cells to form tissue

Question 18

3 Components of the ECM

Answer 18

1) Structural Proteins - glues everything together
e. g. collagen & elastin

2) Specialized Proteins - regulate cell growth & differentiation
e. g. fibronectin & lamin

3) Proteoglycans - trap water
e. g. glycosaminoglycans (GAGs)

Question 19

Connection Tissue

Answer 19

Bunch of cells surrounded by a matrix & ground substance
Function: 
- binding & supporting
- protection against infection
- repair tissue damage
- insulation

Question 20

Loose Connective Tissue

Answer 20

Predominant cell type = adipocytes
Low in structural proteins
Low in ground substances
e.g. adipose tissue

Question 21

Epithelium Classification: Layers

Answer 21

Simple - single layer
Stratified - 2+ layers
Pseudostratified - appear to be multilayered since the nuclei lie on different levels but is actually a single layer

Question 22

Epithelium Classification: Shape

Answer 22

Squamous - flatten out
Cuboidal - cube
Columnar - tall

Question 23

Six Functions of the Skin

Answer 23

1) Thermo-regulation
maintaining body temperature of 37C
2) Blood Reservoir
dermis carries 8-10% of total blood volume
3) Protection
Chemical (oily secretions, melanin UV protection)
Physical (no breaks, thick, keratin)
Biological (immune cells)
4) Cutaneous Sensations
external sensations (pain, temperature, touch)
5) Metabolism
produces Vitamin D
6) Excretion
sweat