35 Homeostasis

Question 1

Collagen Fibers

Answer 1

They appear white, also called white fibers. Collagen is rich in glycine (small optically inactive aa).
Triple helix (tropocollagen). Hydrophobic. H bonding and cross linking occurs through a series of complex reactions between lysine and histidine.

Question 2

Collagen in found

Answer 2

In bone and teeth, collagen in embedded in hydroxyapatite (inorganic calcium phosphate polymer)
Tendons, dentin, dermis, ligaments, and organs all contain collagen.

Question 3

If there’s errors in collagen

Answer 3

Scurvy, ehlers -danlos, osteogensis imperfecta. Vit C is needed for proper collagen synthesis. Proline cannot be hydroxlyated, thus the tropocollagen molecules cannot form a stable helix.
Ehlers Danlos syndrome we see hyper extensive skin and hypermobile joints.

Question 4

Elastic fibers

Answer 4

Unlike collagen, very stretchy. Ability to recoil. Made by fibroblasts and smooth muscle cells in arteries.
Abundant in blood vessels such as the aorta.
Hydrolyzed by pancreatic enzyme elastase.

Question 5

Elastic fibers found in

Answer 5

Bladder, lungs, veins, ligaments, cartilage, and skin.

Question 6

Reticular fibers

Answer 6

Gives support to individual cells. Very thin, branched fibers, made of collagen. Stain black.
Found high% in smooth, muscle, lymph nodes, spleen, and red bone marrow.

Question 7

Connective Tissues are found in

Answer 7

Adipose, Blood, bone, cartilage

Question 8

Connect Tissues and Fibroblast cells

Answer 8

Fibroblast cells synthesize proteins like elastin, collagen, glycoproteins, and proteoglycans of the EcM. Growth factors too

Question 9

Main repair cell

Answer 9

Fibroblast, most abundant cell in CT. They make almost all of the EcM. The EcM surrounds the cells as noncellular component. It provides support but also guides division, growth, and cell development.

Question 10

Fibroblasts make ____

Answer 10

fibronectin. It attaches to the EcM to the cell surface receptor protein such as integrins. Fibronectin is directly involved with wound healing. It migrates into a clot and aids in repair.

Question 11

Nervous Tissue

Answer 11

Endocrine: hormones secreted directly into the bloodstream but targets specific cells that have proper receptors.
Nervous: Transmits info along a specific communication line.

Question 12

Metabolism definition

Answer 12

Sum total of all cellular activities in the body

Question 13

Endotherms

Answer 13

Warmed mainly by metabolism
Used to be called warm blooded
Birds and mammals
Cells usually have more mitochondria
Require more food than ectotherms due to their higher metabolism

Question 14

Ectotherms

Answer 14

Warmed mainly by external sources
Called cold blooded. Blood varies with the ambient temp.
Amphibians, many reptiles, many fish, most invertebrates
Many reptiles reg their body temp by basking in the sun or shade
Consume less food b/c their heat source is from the environment
Can tolerate temp changes.

Question 15

Homeotherm

Answer 15

Constant body temp

Question 16

Poikilotherm

Answer 16

Body temp varies with the environment

Question 17

Most endoterms are

Answer 17

Homeotherms but not all

Question 18

Most ectotherms are

Answer 18

Poikilotherms but not all

Question 19

Body Size and metabolic rate

Answer 19

As we increase body size, we decrease metabolic rate.

Small body mass means the surface to volume ratio is high and the faster it loses heat. It must maintaini a high metabolic rate to fuel cellular oxidative processes.

Question 20

Smaller animals tend to have ___ per gram basal metabolic rates than larger animals

Answer 20

Higher

Question 21

Hibernation

Answer 21

Body temperature and metabolism decrease for long periods of time.