BIO 360 - Exam 1 - Chapter 1 SP 2023 PowerPoint

Question 1

Cells ______ nutrients and wastes with surroundings.

Answer 1

exchange

Question 2

Cells surrounded by what extracellular fluids?

Answer 2

interstitial fluid & blood plasma

Question 3

Cells form ______, ______, & ______ ______that transform and have ______ properties.

Answer 3

Cells form tissues, organs and organ systems that transform and have emergent properties.

Question 4

What are automatic reflexes?

Answer 4

Automatic reflexes detect and respond to deviations of these
variables from their “set point” values

Initiate effector responses that restore variables to optimal range.

Question 5

Body temp is ________ regulated.

A decrease in body temp is a ______ ______.
Sensed by receptors (nerve endings) is a sensor, afferent input.
Information relayed to the hypothalamus, which is the ______ center.
The information from the hypothalamus is the ______ output.
The response (cuddling, shivering thermogenesis, vasoconstriction) is the ______.

Answer 5

Body temp is homeostatically regulated.

regulated variable.
afferent input.
integrating center.
efferent
The response (cuddling, shivering thermogenesis, vasoconstriction) is the effector.

Question 6

What are the questions to ask about homeostatic mechanisms?

Answer 6

(1) What is the variable being regulated?
(2) How is the variable sensed? eg. chemosensor, mechanoreceptor, hormone receptor
(3) Do we know the “set point”?
(4) Where is the information integrated? eg. hypothothalamus
(5) What are the effectors? eg. fibers of sympathetic nervous system
(6) What are targets? eg. smooth muscles surrounding arterioles

Question 7

What are the steps in a reflex pathway?

Answer 7

Stimulus - sensor - input signal - integrating center - output signal - target - response.

Question 8

What happens if we cannot maintain homeostasis?

Answer 8

Failure to compensate, Pathophysiology, Illness, Death

Question 9

How are variables homeostatically regulated?

Answer 9

negative feedback - when a change in a controlled variable triggers a response that opposes the change.

Question 10

Higher basal levels and prolonged elevation of cortisol seen in majority of people suffering from major depression; may also occur during aging, post-trauma?

Answer 10

Abnormal negative feedback in hypothalamicpituitary-
adrenal axis is seen in disease.

Question 11

What is negative feedback?

Answer 11

Negative feedback is when a change in a controlled variable triggers a response that opposes the change - does not imply anything about direction.

Question 12

What is the difference between negative and positive feedback?

Answer 12

Negative feedback: the response counteracts the stimulus, shutting off the response loop. Stays the same, maintains a “set-point.”

Positive feedback: the response reinforces the stimulus, sending the variable farther away from the set-point. The change is “fast.”

Question 13

What do plasma membranes do? (4-things)

Answer 13

• Provide cell structure and support.
• Impermeable membranes serve as barriers to isolate cell chemically or physically.
• Semi-permeable membranes regulate exchange
  between extracellular and intracellular fluid.
• Cell-to-cell communication.

Question 14

What is the Fluid Mosaic Model? (2-things)

Answer 14

• Phospholipids arranged in bilayer - composed of 2 fatty acid chains, bound to glycerol with phosphate gp, and stabilized by cholesterol.
• Two-dimensional fluid of freely diffusing lipids w/embedded proteins. Proteins act as channels, transporters, receptors for extracellular signals.

Question 15

Cartoon of plasma membrane - Organization of polar
and non-polar regions important for understanding
movement into and out of cells.

Question 16

Transporter Proteins: How do channels differ from “carriers?”

Answer 16

Open channels create a water-filled pore. Carriers never form an open channel between two sides of the membrane.