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BIO125 Physiology > Week 1 Principles of physiology I > Flashcards

Week 1 Principles of physiology I Flashcards

1
Q

How are organisms organised? (4 Levels)

A
  1. Cells (basic unit of life)
  2. Tissues = groups of cells with similar specialisation
  3. Organ = unit made up of several tissue types >2
  4. Body system = collection of related organs
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2
Q

Types of Tissues:

Epithelial = ____

Connective = ____

Muscle = ____

Nervous = ____

very diverse, all interconnected. (Integrated response)

A

Epithelial = protection, secretion, absorption

Connective = structural support

Muscle = movement

Nervous = communication, coordination, control

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3
Q

How many systems are there in the body?

A

11

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4
Q

What are the body systems?

A
  • Nervous
  • Immune
  • Reproductive
  • Circulatory
  • Respiratory
  • Muscular
  • Skeletal
  • Integumentary
  • Urinary
  • Endocrine
  • Digestive
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5
Q

Body systems do NOT act in isolation Give an example.

A

Complex body processes - interplay

e.g. regulation of blood pressure

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6
Q

What is an External and Internal Environment?

A

External Environment = surrounding environment in which organism lives

Internal Environment = fluid that surrounds cells

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7
Q

Living organisms need to communicate with external environment. Why?

A

obtain nutrients & O2 & eliminate waste

  • single-celled organism – communicates directly
  • multi-cellular organism – communicates via internal environment
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8
Q

What is Intracellular and Extracellular Fluid ?

A

Intracellular Fluid = fluid contained within body cells

Extracellular Fluid = fluid outside cells > internal environment

  • plasma (fluid portion of blood)
  • interstitial fluid (surrounds & bathes cells)
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9
Q

What is the key to Homeostasis?

A

Internal Environment, fluid that surrounds cells –> interstitial fluid (surrounds & bathes cells)

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10
Q

What is homeostasis?

Why is it the foundation of physiology?

A

Homeostasis = maintenance of a stable internal environment

homeo ‘similar’
stasis ‘to stand or stay’

  • cells make up body systems
  • functions of each body system contribute to homeostasis
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11
Q

What is the dynamic steady-state in Homeostasis?

A
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12
Q

What factors are homeostatically maintained?

A

• nutrient molecules – energy production

  • waste products – may be toxic
  • O2 & CO2
  • pH – nerve cells & enzymes
  • water, salts, electrolytes
  • cell volume, rhythmic beating of heart (K+)
  • temperature - enzymes
  • volume & pressure - plasma
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13
Q

Homeostatic control mechanisms may be intrinsic or extrinsic. What does this mean?

A

Intrinsic / local
intrinsic = within
•inherent in an organ
(e.g. exercising skeletal muscle – vasodilation of blood vessels)

Extrinsic / systemic
extrinsic = outside of
•initiated outside an organ to alter its activity (mediated by nervous & endocrine systems)
(e.g. blood pressure – nervous system acts on heart & blood vessels –> coordinated regulation to achieve common goal)

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14
Q

What do homeostatic control mechanisms operate on? How does this work?

A

principle of negative feedback

  • change in controlled variable triggers response to oppose that change
  • drives variable in opposite direction of initial change
  • maintains level of specific variable within given range/set point
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15
Q

How does the negative feedback system function?

A
  • Detects change away from set point
  • Initiates mechanisms to correct situation
  • Shuts itself off
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16
Q

What are the components of a negative feedback control system? (6 points)

A
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17
Q

What are the components of a negative feedback control system in terms of body temperature? (6 points)

A
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18
Q

What is positive feedback? How does it work?

A

Rare within the body (opposes homeostasis)

  • control variable continues to move in the direction of initial change
  • reinforce the change in same direction > moves away from set point

(e.g. release of oxytocin during end stages of pregnancy)

19
Q

What is the posititive feedback loop in Parturition?

A

fetus changes position

  • pressure on cervix
  • stretch-sensitive cells stimulated
  • impulse → brain
  • oxytocin released
  • uterus contracts
  • ↑ pressure on cervix
  • ↑ stimulus on stretch-sensitive cells
  • ↑ oxytocin
  • stronger uterine contractions
  • POSITVE FEEDBACK LOOP

continues until fetus expelled & stimulus removed

20
Q

What is the First law of thermodynamics?

A
  • energy can neither be created or destroyed
  • energy input = energy output
21
Q

What is energy imput in terms of ingested food?

A

ingested food > energy harvested > used for biological work or stored

22
Q

What is Energy output in terms of external work & internal work?

A

External work = energy expended by skeletal muscles (moving external objects)

  • *Internal work** = all other forms of biological energy expenditure 1.Skeletal muscle activity (posture, shivering)
    2. Energy-expending activities required to sustain life (pumping blood)
23
Q

What is the #1 ATP consumer?

A

The Heart

  • 6 KG ATP per day, 20-30 x its own weight
  • 100,000 beats, 10 tons of blood/day
24
Q

What process describes how energy is produced?

A

Oxidative Phosphorlyation

25
Q

What is the overview of oxidative phosphorylation?

  • ATP is formed as a result of what?
  • Where does this take place?
  • How much ATP does it generate? How?
A
  • ATP is formed as a result of the transfer of electrons from NADH or FADH2 to O2 by a series of electron carriers.
  • Takes place in mitochondria, is the major source of ATP in aerobic organisms
  • Generates 26 of the 30 molecules of ATP that are formed when glucose is completely oxidized to CO2 and H2O.
26
Q

What is Oxidative Phosphorlyation?

A
27
Q

What process describes how fuel is produced from food?

A

Metabolic Substrate Utilization

28
Q

What is ​Metabolic Substrate Utilization?

A
29
Q

What is the ATP Transfer Mechanism?

A
30
Q

Step process of thermodynamics in the body:

A
31
Q

Define Metabolic Rate (MR).

A

rate at which energy expended by the body per unit of time

  • most of body’s energy expenditure eventually appears as heat
  • MR expressed as rate of heat production/hr (kcal/hr)
  • 1kcal = 1000calories = 4187J = 4.18kJ
32
Q

What are the factors that influence MR?

  • Muscular activity
  • Food intake
  • Shivering
  • Anxiety
  • Fasting & malnutrition
  • Fever
  • Hormones - catecholamines, growth hormone, thyroid hormone
A
  • Muscular activity (↑) (most strong influence)
  • Food intake (↑)
  • Shivering (↑)
  • Anxiety (↑)
  • Fasting & malnutrition (↓)
  • Fever (↑)
  • Hormones - catecholamines, growth hormone, thyroid hormone (↑)
33
Q

Define Basal metabolic rate (BMR).

A
  • index of metabolism under standardised conditions
  • minimal waking rate of internal energy expenditure
34
Q

What are the Standardised basal conditions?

A
  • awake
  • relaxed & rested (>30 min)
    • physical & mental
  • supine
  • warm (TNZ 20-25oC)
  • fasting (8-12hr)

BMR - 20-25 kcal/kg body weight/day

35
Q

How is BMR Measured?

A

direct or indirect calorimetry

Indirect Calorimetry

  • practical & less costly
  • O2 uptake per unit of time is measured
  • Food + O2 –> CO2 + H2O + energy (mostly heat)
  • direct relationship between O2 consumed & heat produced
    • depends on type of food being oxidised
      • energy equivalent value for complete oxidation of food
36
Q

Which of the following will increase BMR?

  1. Sleep
  2. Chronic exposure to a cold environment
  3. Areductionin circulating thyroid hormone
  4. Low body weight
  5. Ageing beyond 20 years
A
  1. Sleep
  2. Chronic exposure to a cold environment
  3. Areductionin circulating thyroid hormone
  4. Low body weight
  5. Ageing beyond 20 years
37
Q

What are the Factors that influence BMR?

A
  • Age (BMR ↑ in children but ↓ with age)
  • Gender ( ↓ in females)
  • Genetic determinants (not well defined)
  • Lean body mass (body fat %)
  • Body weight (­ ↑ in obesity)
  • Body surface area (taller people have ↑ BMR)
  • Environmental temperature
  • Sleep (↓ 10-15%)
  • Hormones – thyroid hormone, catecholamines
38
Q

List 4 things that are homeostatically maintained by the body.

A
  1. O2 & CO2
  2. pH – nerve cells & enzymes
  3. temperature - enzymee
  4. volume & pressure - plasma
39
Q

What 4 tissue types exist within the human body?

A
  1. Epithelial
  2. Connective
  3. Muscle
  4. Nervous
40
Q

What 2 components make up the ECF (Extracellular fluid)?

A
  1. plasma (fluid portion of blood)
  2. interstitial fluid (surrounds & bathes cells)
41
Q

Extrinsic control systems are mediated by which body systems?

A

mediated by nervous & endocrine systems

42
Q

Does shivering increase or decrease MR?

A

increase

43
Q

Positive feedback acts to maintain homeostasis. T/F?

A

False.

Positive feedback acts to oppose homeostasis

BIO125 Physiology (17 decks)

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