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KIN 3306 Unit 1 > Ch 2 Control of the Internal Environment > Flashcards

Ch 2 Control of the Internal Environment Flashcards

1
Q

What are control mechanisms?

A

Allows the human body to maintain a relatively constant internal environment in spite of stressors

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2
Q

What is homeostasis?

A

the maintenance of a relatively constant internal environment

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3
Q

What is a steady state (in contrast to homeostasis)?

A

a steady state represents physiological variables that are unchanging and constant

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4
Q

T or F
The French physiologist Claude Bernard observed that the internal environment of the body constantly varied with change in the external environment.

A

FALSE; Claude Bernard observed that the internal environment of the body remained REMARKABLY CONSTANT DESPITEEE a changing external environment

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5
Q

Give an example of steady state

A
  • Heart rate; although it changes constantly (80-90bpm for one heart beat), it still maintains a constant rate within the beat

IN CONTRAST TO HOMEOSTASIS LIKE SWEATING WHEN THE WEATHER IS HOT

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6
Q

T or F

Homeostasis is generally reserved for describing normal resting conditions

A

True

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7
Q

Where does the most intricate of the control systems in the body reside in?

A

the cells

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8
Q

What are the elements of a biological control system?

A

1) a sensor or receptor
2) a control center (i.e. center to integrate response)
3) effectors (i.e. organs that produce the desired effect)

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9
Q

A biological control system is composed of how many elements?

A

3; three

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10
Q

The sensor, upon excitation by a stimulus, sends a message to the

a) efferent nervous system
b) receptor
c) control center
d) effector

A

c) control center

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11
Q

The control center signals the __ to bring about an appropriate response to correct a disturbance

a) isotope
b) receptor
c) sensor
d) effector

A

d) effector

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12
Q

Identify the cell activities that are regulated by cellular control systems

A

breakdown of proteins and energy production

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13
Q

What is a biological control system?

A

a series of interconnected components that maintain a chemical or physical parameter of the body near a constant value

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14
Q

A type of feedback loop that is the primary method responsible for maintaining homeostasis

A

negative feedback loop

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15
Q

This excites a sensor and is the signal to begin the operation of a control system, thus representing a change in the internal environment

A

stimulus

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16
Q

T or F

A majority of the control systems of the body operate via positive feedback

A

FALSE; mostly operate via negative feedback

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17
Q

What is negative feedback?

A

an important class of biological control systems in the body that serves to restore normal values of a variable to maintain homeostasis

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18
Q

The __ integrates the strength of an incoming signal from the sensor

A

control center

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19
Q

When homeostasis is established via the negative feedback mechanism, physiological events result in

A

negating the initiating stimulus;

giving an opposite response from the initial stimulus to maintain homeostasis

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20
Q

Give an example of positive feedback control system

A
  • enhancement of labor contractions when a woman gives birth
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21
Q

Give an example of a negative feedback control system

A
  • low body temp leads to shivering to increase body heat
  • high body temp leads to sweating to decrease body heat
  • increasing blood glucose levels triggering the release of insulin to metabolize (decrease) sugar
22
Q

During labor, increased pressure on the cervix stimulates sensory receptors that trigger the release of oxytocin. Oxytocin in turn promotes increased contractions. This is a classic example of _____.

A

positive feedback

23
Q

What is the gain of a control system?

A

the precision with which a control system maintains homeostasis

24
Q

In thermoregulation, the hypothalamus receives information about the changes in body temperature and establishes homeostasis by directing appropriate responses. In this instance of negative feedback, the hypothalamus functions as the _____.

A

control center;

hypothalamus RECEIVES information, NOT TRIGGERED. If hypothalamus was TRIGGERED then it would be sensor but since it is RECEIVING information and DIRECTING appropriate responses (probably to the effectors) then it is a control center

25
Q

control systems that deal with life-and-death issues

a) maintain true homeostasis
b) are capable of establishing new set points
c) have large gains
d) have small gains

A

have large gains

26
Q

When body temperature increases above normal, homeostatic control via negative feedback is triggered by the _____.

A

thermal receptors in the body

27
Q

A control system with a large gain is ___.

a) slower in returning to homeostasis
b) more prone to homeostatic disturbances
c) more capable of correcting homeostatic disturbances
d) less capable of returning the system to homeostasis

A

c) more capable of correcting homeostatic disturbances

28
Q

The eight major endocrine glands synthesize and secrete blood-borne chemical substances called what?

A

hormones

29
Q

Identify a process that is controlled by systems with large gains

A

regulation of body temp, breathing, and delivery of blood throughout the body

30
Q

Where is the control center located in the context of regulation of body temperature?

A

in the brain

31
Q

When the thermoregulatory control center directs the blood vessels in the skin to constrict, _____.

A

body heat is conserved; shivering occurs

32
Q

When the thermoregulatory control center directs the blood vessels in the skin to dilate, _____.

A

sweating occurs; to promote heat loss

33
Q

The endocrine system regulates blood glucose concentration by the hormone _____.

A

insulin

34
Q

The failure of a blood glucose control system to correct disturbances in homeostasis results in _____.

a) a steady state
b) disease
c) autoimmunity
d) a new set point

A

b) disease

35
Q

the maintenance and control of blood glucose levels for homeostasis is a function of what system?

A

endocrine system

36
Q

Muscular exercise presents a dramatic test of the body’s homeostatic control systems because it results in large

a) amounts of heat production
b) increases in muscle O2 production
c) increases in muscle CO2 requirements
d) amounts of O2 accumulation

A

a) amounts of heat production

37
Q

What are the sensors and control centers for change in body temp (either increase of decrease above normal)?

A

sensors -> thermal receptors in the body
control center -> hypothalamus in the brain

THIS WASN’T ASKED FOR BUT
effectors -> IF COLD = shiver and IF HOT = sweat

38
Q

The cell’s ability to respond to a challenge can be

a) improved by prolonged exposure to a specific stress
b) can become severely limited on prolonged exposure to a specific stress

A

a) improved by prolonged exposure to a specific stress

39
Q

What is acclimation?

A
  • the improved function of an existing homeostatic system
  • the change that occurs in response to repeated environmental stresses and results in the improved function of an existing homeostatic system
  • ex: cells can adapt to heat stress due to a hot environment by the production of heat shock proteins.
40
Q

What is adaptation?

A

a change in the structure and function of a cell or an organ system that results in an improved ability to maintain homeostasis during stressful conditions

41
Q

Intracrine signaling is a form of cell signaling mechanism wherein a chemical messenger _____.
a) moves from one cell to the neighboring cell
b )acts on nearby cells to bring about a coordinated response
c) triggers a signaling pathway within the same cell
d) travels by the blood stream throughout the body to target cells

A

c) triggers a signaling pathway within the same cell

42
Q

What is intracrine signaling?

A

occurs when a chemical messenger is produced inside a cell that triggers a signaling pathway within the same cell that leads to a specific response

43
Q

What is juxtacrine signaling?

A

occurs when the cells communicate by cell-to-cell contact, in which the cytoplasm of one cell is in contact with the cytoplasm of another through small junctions that connect the two cell membranes

i.e. the method by which one heart cell signals to an adjacent cell to contract

44
Q

What is autocrine signaling?

A

occurs when a cell produces and releases a chemical messenger into the extracellular fluid that acts upon the cell producing the signal

i.e. resistance training; muscle cell triggers the DNA in the nucleus to produce more contractile protein which in turn increases the size of that muscle cell

45
Q

What is paracrine signaling?

A

occurs when cells produce signals that act locally on nearby cells to bring about a coordinated response

i. e. how immune cells communicate with each other to generate a coordinated attack to protect the body from infection and injury.
ex2: synaptic signaling

46
Q

What is endocrine signaling?

A

occurs when cells release chemical signals (hormones) into the blood and these hormones are then carried throughout the body

47
Q

The signaling mechanism in which a cell contacts another cell through small junctions that connect the two cell membranes is called _____ _______.

A

juxtacrine signaling

48
Q

In autocrine signaling, the chemical messenger is _____.

a) sent to nearby cells to bring about a coordinated response
b) released into the extracellular fluid
c) used to trigger a signaling pathway within the same cell
d) carried by the blood stream throughout the body to target cells

A

b) released into the extracellular fluid

49
Q

In paracrine signaling, chemical messengers are released _____.

a) to trigger pathways within the same cell
b) via junctions into the adjacent cell
c) into the blood to travel to remote target cells
d) to act on nearby cells

A

d) to act on nearby cells

50
Q

Identify the cell signaling mechanism that occurs when a chemical messenger is produced inside a cell that triggers a signaling pathway within the same cell.

A

intracrine signaling

51
Q

The cell signaling mechanism that acts locally to bring about a coordinated response is called _____ signaling.

A

paracrine signaling

KIN 3306 Unit 1 (5 decks)

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