Homeostasis

Question 1

Physiology

Answer 1

Physio: natural causes and phenomena
Ology: the study of

Question 2

Body- function

Answer 2

• explains “why” something happens
• Teleological approach

Question 3

Body- process or mechanism

Answer 3

• describes the “how” something happens
• mechanistic approach

Question 4

Metabolism

Answer 4

sum of all chemical reaction in the body

Question 5

responsiveness

Answer 5

react and change to environment

Question 6

movement

Answer 6

• change in pace, posture, position or place
• internal: movement of substances within the body
• External: move either pats or entire body from place to place

Question 7

Growth

Answer 7

increase in the number and size of cells In an organism

Question 8

Differentiation

Answer 8

less specialized cell matures to a more distinct form and function

Question 9

reproduction

Answer 9

production of offspring by organized bodies

Question 10

Cells

Answer 10

basic structural and functional units of an organism

Question 11

Tissues

Answer 11

consist of groups of similarly specialized cells and the substances surrounding them that usually arise from a common ancestor and perform certain special functions

Question 12

Organs

Answer 12

are structures of definite form that are composed of two or more different tissues and have specific functions

Question 13

Systems

Answer 13

consist of related organs that have a common function.

Question 14

Human organism

Answer 14

is a collection of structurally and functionally integrated systems; any living individual

Question 15

Homeostasis

Answer 15

• Is a condition of equilibrium, or balance, in the body’s internal environment
• maintained by the body regulatory processes

Question 16

To maintain homeostasis, control system must:

Answer 16

– detect deviations from normal in the internal environment that need to be held within narrow limits
– integrate this information with other relevant information
– make appropriate adjustments to restore a factor to its desired value

Question 17

Set point

Answer 17

normal range for a given system , will be monitored by the control centre for that particular system

Question 18

Circadian Rhythm

Answer 18

Circadian rhythms are endogenous autonomous oscillators of physiological activities that result in an ~24 hour day/night cycles, which allow organisms to adapt to a fluctuating environment
* The circadian clock system is a major regulatory factor for nearly all physiological activities and its disorder can have severe consequences on human health.

Question 19

Intrinsic controls

Answer 19

local controls that are inherent in an organ

Question 20

Extrinsic controls

Answer 20

• regulatory mechanisms initiated outside an organ
• accomplished by nervous and endocrine systems

Question 21

Dynamic equilibrium adjustments

Answer 21

Feedback loops: responses made after a change, negative or positive
Feedforward loops: responses made in anticipation of a change

Question 22

The basic components of a feedback loop

Answer 22

stimulus-> controlled condition-> receptors-> control center-> effectors-> response that alters the controlled condition-> -> return to homeostasis, brings controlled condition back to normal

Question 23

Negative feedback loop

Answer 23

• opposes initial change
• components:
  Sensor: monitors magnitude of a controlled variable
  Control centre: campares sensor’s input with a setpoint
  effector: Makes a response to produce a desired effect

Question 24

Negative feedback main goal

Answer 24

• keeping internal environment stable
• only control within the body, not what is in the outside world
  Ex: temperature, nutrients/waste, O2/CO2 levels, ph, water/eletrolytes, blood volume and pressure

Question 25

Positive feedback loop

Answer 25

• Amplifies an initial change and therefore does not truly contribute to homeostasis
• Does not occur as often as negative feedback systems
  – Abnormal changes move the body farther away from homeostatic balance and, potentially, toward death.

Question 26

Positive feedback main goal

Answer 26

• Response reinforces the stimulus
• snowball effect (gets bigger and bigger and bigger - rolling a snowball down a hill)
  Ex: Contractions during labour

Question 27

Homeostatic imbalances

Answer 27

Disruption of homeostasis can lead to disease and death

Question 28

Disorder

Answer 28

is a general term for any derangement of abnormality of function

Question 29

Disease

Answer 29

is a more specific term for an illness characterized by a recognizable set of signs and symptoms

Question 30

Aging and homeostasis

Answer 30

aging is a normal process characterized by a progressive decline in the body’s ability to restore homeostasis

Question 31

Feedforwrd mechanisms and anticipation

Answer 31

Although not as common in the body as negative feedback loops, there are mechanisms which are activated before a change in a variable actually occurs.
- These mechanisms attempt to anticipate changes before they occur, rather than responding to a change after it has occurred.
Ex: digestion: saliva production prior to eating, food in digestive tract (increase secretion of insulin to promote cellular uptake and storage of nutrients)

Question 32

Feedforward central command

Answer 32

Primes the body for the changes that are about to take place during the exertion
– Oxygen demand increases to working muscles
– Cardiac output increases up to 6-7x
– Oxygen extraction rates can increase 2-3x