Exam 1

Question 1

Type I Collagen, composition, location and function.

Answer 1

Composition: [a1II)]2a2(I)
Location: CT tissue of skin, bone, tendon, ligaments, dentin, sclera, fascia, and organ capsules (accounts for 90% of body collagen)
Functions: Provides resistance to force, tension, and stretch

Question 2

Type II Collagen, composition, location and function.

Answer 2

Composition: [a1 (II)]3
Location: Cartilage (hyaline and elastic), notochord, and intervertebral disk
Functions: Provides resistance to intermittent pressure.

Question 3

Type III Collagen, composition, location and function.

Answer 3

Composition: [a1 (III)]3
Location: Prominent in LCT and organs, (uterus, liver, spleen, kidney, lung etc); smooth muscle; endoneurium; blood vessels; and fetal skin
Functions: Forms reticular fibers, arranged as a loose meshwork of thin fibers, provides a supportive scaffolding for the specialized cells of various organs and blood vessels.

Question 4

Type IV Collagen, composition, location and function.

Answer 4

Location: Basal laminae of epithelia, kidney glomeruli, and lens capsule
Function: Provies support and filtration barrier

Question 5

Type V Collagen, composition, location and function.

Answer 5

Location: Distributed uniformly throughout CT stroma; may be related to reticular network
Functions: localized at the surface of type I collagen fibrils along with the type XII and XIV collagen to modulate biomechanical properties of the fibril

Question 6

Elastic fibers

Answer 6

Elastic (allows for elasticity)
Found in several organs and structures where elastic properties are useful:
Arteries
Airways structures (trachea, bronchi, lung tissue)
Ear
Epiglottis

Question 7

Protoglycans and glycosaminoglycans secrete what?

Answer 7

-Ground substance
Hyaluronic acid
Chondroitin sulfate
Dermatan sulfate
Keratin sulfate

Question 8

Hyaline cartilage

Answer 8

Firm and Flexible closely packed collagenous fibers embedded in a “glassy” appearing matrix (i.e. articular surfaces, costal cartilage, trachea rings).

Question 9

Elastic cartilage:

Answer 9

Firm and elastic looser collagenous fibers with abundant elastic fibers (i.e. ear, epiglottis)

Question 10

Fibrocartilage

Answer 10

Firm and compressible somewhat regular arrangement of thick collagenous bundles (intervertebral discs, pubis symphysis, knee).

Question 11

What is bone formed by? which cell type

Answer 11

-Osbteoblasts; Collagenous fibers (Primarily type I collagen) that have been mineralized with a ground substance call hydroxyapatite (calcium phosphate)

Question 12

Granulocytes

Answer 12

Neutrophils (or Polymorphoneutrophils : PMN’s)
Eosinophils
Basophils

Question 13

Agranulocytes

Answer 13

Monocytes

Lymphocytes

Question 14

Percentage of Granulocytes

Answer 14

Neutrophils: 55 - 60%
Eosinophils: 2 - 5%
Basophils: 0 - 1%

Question 15

Percentage of Agranulocytes

Answer 15

Lymphocytes: 30 - 35%
Monocytes: 3 - 7%

Question 16

Brown vs White Fat

Answer 16

Brown fat found in newborns and kids and diminishes with age

White fat – typical fat found throughout the body

Question 17

Brown fat function

Answer 17

Serves as an energy source for heat in newborns and the young via thermogenesis.
Trigged by cold temperature and norepinephrine via sympathetic nervous system
Mitochondria well developed and more abundant
Also more abundant in hibernating animals

Question 18

Two types of astrocytes

Answer 18

Protoplasmic astrocytes – found in gray matter
Multiple short branching processes
Fibrous astrocytes – found in white matter
Fewer straight processes

Question 19

Functions of Astrocytes

Answer 19

Astrocytes have an intimate relationship with endothelial cells and their tight junctions
Transports essential nutrients to the neurons – glucose, amino acids, vitamins via carrier proteins
Protects the CNS from fluctuating levels of electrolytes, hormones and metabolites
O2 and CO2 can however can pass through the extracellular matrix

Question 20

Functions of Schwann Cell

Answer 20

Schwann cells produce the myelin sheath around the axons of nerves in the peripheral nervous system
Lipid rich structure that insulates the axon from the extracellular environment
Forms “Nodes of Ranvier” that accelerate the action potential
Also support non-myelinated axons

Question 21

Skeletal Muscle: Cross bridge cycle

Answer 21

Ca 2+ is released from the sarcoplasmic reticulum and reacts with troponin
Tropomyosin then undergoes a conformational change exposing the attachment point of the actin
The heads of the activated myosin (pre charged by ATP converted to ADP) crossbridges with actin
ADP is released and the energy contracts and shortens the myofibrial
The myosin head is recharged to ATP and the cycle continues (as long as Ca +2 ions are present)