Week 1 Physiology Flashcards

1
Q

Homeostasis

A

State of body equilibrium or stable internal environment of the body, achieved through coordinated physiological activity

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2
Q

Feedback loops

A

A process conducted by the body in response to a change to maintain homeostasis

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3
Q

Features of a feedback loop

A
  • Stimulus
  • Receptors
  • Control centre
  • Effectors
  • Response
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4
Q

Stimulus

A

Disrupts homeostasis by increasing or decreasing a controlled condition

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5
Q

Receptors

A

Detects the change in environment, sends nerve impulses or chemical signals to the control centre (brain)

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6
Q

Control centre (brain)

A

Receives the input and provides nerve impulses or chemical signals to the effectors, giving an idea of how to respond to the change

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7
Q

Effectors

A

Bring about a change or response to return to homeostasis

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8
Q

Response

A

Alters the controlled condition

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9
Q

Types of feedback loops

A
  • Negative feedback
  • Positive feedback
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10
Q

Negative feedback loops

A

Feedback which reduces (or opposes) the intensity of the original stimulus
Examples:
* Blood pressure
* Glucose levels
* Respiratory rate
* Water reabsorption by kidneys
* pH level of blood
* Body temperature

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11
Q

Positive feedback loops

A

Feedback which increases (or enhances) the intensity of the original stimulus
Examples:
* Stretching of the cervix during childbirth
* Production of prolactin (breast milk)
* Blood clotting (heal wounds by forming a scab)

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12
Q

3 main components of cells (name)

A
  • Cell membrane
  • Cytoplasm
  • Nucleus
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13
Q

Cell membrane

A
  • Outer barrier of the cell
  • Regulates what crosses the membrane - enables the cell to have a stable environment
  • Phospholipid bilayer
  • Selectively permeable
  • Generally negatively charged
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14
Q

Cytoplasm

A

Intracellular fluid that contains organelles (e.g. cytosol, organelles)

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15
Q

Nucleus

A

Contains our genetic material – DNA (e.g. chromosomes, genes)

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16
Q

Osmosis

A

Diffusion of water molecules across membrane

17
Q

Hypertonic solution

A

High solute concentration

18
Q

Hypotonic solution

A

Low solute concentration

19
Q

Isotonic solution

A

Equally solute concentration

20
Q

Concentration gradient

A

Underlies the movement in all types of active transport, is the force of movement

21
Q

Moving down the concentration gradient

A

Moving something from an area of high concentration to an area of low concentration

22
Q

Moving against the concentration gradient

A

Moving something from an area of low concentration to an area of high concentration

23
Q

Membrane transport processes

A

Passive transport - no energy required:
* Simple diffusion
* Channel-mediated facilitated diffusion
* Carrier-mediated facilitated diffusion
Active transport - lots of energy required, force of movement is adenosine triphosphate (ATP):
* Primary active transport
* Secondary active transport

24
Q

Simple diffusion

A

Non-polar and non-charged particles pass through easily, no facilitation required (e.g. oxygen, carbon dioxide)

25
Channel-mediated facilitated diffusion (definition)
Requires protein channel to help electrolytes cross the membrane (e.g. potassium, sodium, magnesium, calcium)
26
Carrier-mediated facilitated diffusion (definition)
Requires protein carrier, changes shape to allow large substances to cross membrane (e.g. trans membrane proteins such as glucose)
27
Primary active transport (definition)
* Uses sodium potassium pump (most common) * Uses ATP directly * Rule: pumps out 3 sodium ions against the concentration gradient and pumps in 2 potassium ions down the concentration gradient * Allows the cell to maintain its specific negative charge
28
Secondary active transport (definition)
* Sodium movement enables electrolytes and vitamins to cross the membrane * Can only occur after primary active transport has occurred first as it sets up a concentration gradient of sodium by moving sodium out of the cell * Allows sodium ions to move back down its concentration gradient passively * Can take a second molecule across with it * Uses ATP indirectly * Allows glucose and amino acids to easily enter the cell * Involves symporters and antiporters
29
Symporters
Two molecules can cross the protein in the same direction (e.g. sodium and glucose, amino acids, electrolytes)
30
Antiporters
Two molecules can cross the protein in the opposite direction (e.g. sodium in, calcium or hydrogen out)