Quiz 1

Question 1

List the four intracellular junctions

Answer 1

Tight Junctions, Desmosomes, Gap Junctions and Adherence Junctions

Question 2

Describe Tight Junctions

Answer 2

“Water tight” prevents extracellular fluid from traveling between cells. Usually on the apical surfaces of the cell.

Question 3

Describe Desmosomes

Answer 3

Structural junction with exposed membrane on all sides. Think rebar and allows fluid to pass around it. (Muscles or Skin)

Question 4

Describe Gap Junctions

Answer 4

Allows for fluid to pass quickly between cells. Great for electrical signals or second messenger from cell to cell. (Muscles)

Question 5

Describe Adherence Junctions

Answer 5

holds EPITHELIAL cells together & help them resist separation during CONTRACTILE activities (passage of foods through intestine)

Question 6

What is Homeostais

Answer 6

Homeostasis refers to the dynamic mechanisms that detect and respond to deviations in physiologic variables from their “set point” values by initiating effector responses that restore the variables to the optimal physiological range.

Question 7

(Broadly) How does Homeostasis create a steady state?

Answer 7

Using water and other dissolved subtsances as transporters and communicators.

Question 8

What are Body Fluids

Answer 8

the watery solution of dissolved substances (oxygen, nutrients, etc.) present in the body. Fluids can be divided into Intracellular Fluid (ICF) and Extracellular Fluid (ECF).

Question 9

What is Extracellular Fluid (ECF)?

Answer 9

The fluid in the blood and surrounding the cells (i.e., outside the cell).

Question 10

How is Extracellular Fluid (ECF) proportioned or distributed in the body?

Answer 10

About 25% of ECF is in the fluid portion of blood (plasma) and the remaining 75% of the ECF lies around and between cells and is known as the interstitial fluid.

So… EFC = Blood + interstial fluid

Question 11

What is Endocytosis

Answer 11

A process where a section of a cell’s membrane enfolds subtances from outside, spearates from the membrane and moves inside the cell

Question 12

What is Exocytosis?

Answer 12

Discharge or secretion of material from intracellular vesicles

Question 13

why large organisms are multicellular?

Answer 13

To have a high surface-to-volume ratio. So cells in the human body are within a few cell layers of a capillary, and every cell is in contact with interstitial fluid.

Question 14

What are the four main tissue types?

Answer 14

Connective Tissue (include blood)

Epithelial Tissue

Muscle Tissue

Nervous Tissue

Question 15

Define Diffusion

Answer 15

Movement of a solute molecule from an area of greater concentration to an area of lesser concentration.

Question 16

What are some things which can diffuse (passive) across a plasma membrane?

Answer 16

Hydrophobic molecules (O2, CO2, N2)

Small unchrged molecules ( H20, urea)

Question 17

What is Hydrostatic pressure?

Answer 17

Mechanical force of water pushing against cellular membranes. (example in vascular system is blood pressure)

Question 18

Describe Osmosis

Answer 18

The movement of water “down” a concentration gradient. Always from a higher concentration to a lower one.

Question 19

Describe mediated transport (passive)

Answer 19

Comformational Change Model and Channel Model

Comformational Change doesnt require ATP but uses binding sites to shuttle molecules inside

Channel Mode is a channel which allows for faster diffusion of certain ions

Question 20

What are the four ways cells communicate or signal?

Answer 20

Autocrine

Paracrine

Endocrine

Nervous

Question 21

Describe how Autocrine signaling works

Answer 21

A cell’s receptor detects the molecule it has produced and exocytosed

Many cells use this as a method of negative feedback—

If there’s enough signaling molecule around to bind to the autocrine receptor, then the cell should save its energy and quit making it.

Question 22

Describe the Paracrine system

Answer 22

Short distance signals

Messenger chemicals have a short lifespan

Messengers have high specificity to their receptors (no mistakes)

(Exampe NO)

Question 23

Describe the Endocrine system (signaling)

Answer 23

Cells talking to other cells from near to far

• Lower specificity
• Goal is for one organ to give guidance across many cells or organ types

Question 24

Describe Neuroendocrine (signaling)

Answer 24

When the nervous system talks directly to the endocrine system

-Usually a faster signal that lasts longer

Question 25

Describe a “positive feedback” system

Answer 25

In a positive feedback system, the output enhances the original stimulus.

A good example of a positive feedback system is child birth. During labor, the hormone oxytocin is released that intensifies and speeds up contractions

Question 26

Describe a “negitive feedback” system

Answer 26

A stimulus or “affect” casues a series of effects

Example: Body temperature rises (affect)

Sweat is produced (action)

Temp returns to normal (effect)

Negative feedback is more common for homeostais!!!!

Question 27

Define Hormone

Answer 27

a chemical messenger secreted into the blood by cells of the endocrine system. Hormones may act on many different cells simultaneously because they circulate throughout the body, everywhere that blood goes.

Question 28

Physiology vs Pathophysiology

Answer 28

When homeostasis is maintained, we refer to it as physiology; when it is not, we call it pathophysiology.

Question 29

Describe Steady State

Answer 29

A system that is in a steady state remains constant over time, but that constant state requires continual work. (Requires energy)

Ionic compounds are maintained at constant concentrations in cells, but only through continually moving ions across the cell membrane.

For example, the potassium concentration in animal cells is maintained by active transport of ions up electrochemical gradients into the cell. Ecosystems may also exist in steady states.

Question 30

Decribe Equilibrium

Answer 30

system at chemical equilibrium, or just equilibrium, is stable over time, but no energy or work is required to maintain that condition.

Question 31

Define erythropoietin (EPO) and describe its role in red blood cell formation

Answer 31

Erythropoietin is a hormone scripted by the kidneys that increases the rate of production of red blood cells in response to falling levels of oxygen in tissues (Hypoxia).