Principles of Physiology Flashcards
1
Q
What is physiology?
A
The study of the functions of living things
2
Q
Physiology describes how processes in the body work by explaining their…
A
mechanisms of action
3
Q
What are the levels of organisation in the body?
A
Cells
Tissues
Organs
Organ systems
4
Q
What is a cell?
A
The basic unit of life
5
Q
What is a tissue?
A
Groups of cells with similar specialisation
6
Q
What are the four primary types of tissue in the human body?
A
Epithelial
connective
muscle
nervous
7
Q
What is the function of epithelial tissue?
A
Provide protection
secretion
absorption
8
Q
What is the function of the connective tissue?
A
To provide structural support
9
Q
What is the function of muscular tissue?
A
For movement
10
Q
What is the function of the nervous tissue?
A
Involved in communication coordination and control
11
Q
Name an organ which is made up of all four primary types of tissue
A
The stomach
12
Q
What is an organ?
A
A unit made up of several tissue types - >2
13
Q
What is a body system?
A
A collection of related organs
14
Q
How many body systems exist?
A
11
15
Q
List the 11 body systems
A
nervous immune reproductive circulatory respiratory muscular skeletal integumentary urinary endocrine digestive
16
Q
Why do body systems not act in isolation?
A
There are complex body processes which require an interplay between different body systems
17
Q
Give an example of a regulatory process which requires more than one body system
A
Regulation of blood pressure nervous system circulatory system endocrine system urinary system
18
Q
What is the external environment?
A
The surrounding environment in which an organism lives
19
Q
What is the internal environment?
A
The fluid that surrounds cells
20
Q
Why do living organisms need to communicate with the external environment?
A
Obtain nutrients and o2 and to eliminate waste
21
Q
Why is it easier for unicellular organisms to communicate with the external environment?
A
They can communicate directly whereas multicellular organisms have to communicate via the internal environment
22
Q
What two parts make up the internal environment?
A
The intracellular fluid and the extracellular fluid
23
Q
What is intracellular fluid?
A
Fluid that is contained within body cells
24
Q
What is extracellular fluid?
A
fluid that is contained outside cells but is still in the internal environment
25
What two parts make up the extracellular fluid?
The plasma and the interstitial fluid
26
What is the plasma?
The fluid portion of the blood
27
What is the interstitial fluid?
The fluid that surrounds and bathes cells
28
The interstitial fluid is key to
homeostasis
29
What is homeostasis?
The maintenance of a stable internal environment
30
What does the homeo and the stasis part of homeostasis mean?
Homeo means similar and stasis means to stand or stay
31
Why is homeostasis often said to be the foundation of physiology?
Cells make up the body systems and the functions of each body system contribute to homeostasis
32
Homeostasis is not rigid, it is a
dynamic process
33
Many factors are homeostatically maintained, give some examples.
```
Nutrient molecules
o2 and co2 concentration
conc of waste products
pH
conc of h20, salts and other electrolytes
vol and pressure
temperature
```
34
Why does the concentration of nutrients have to be maintained?
Cells need a constant supply of nutrient molecules for energy production
35
Why does the concentration of oxygen and carbon dioxide need to be maintained?
Oxygen - for energy yielding reactions
| Carbon dioxide - must be removed so acid forming co2 does not increase the acidity of the internal env
36
Why does the conc of water products need to be maintained?
some chemical reactions produce end products that are toxic if accumulated
37
Why does the pH have to be maintained?
Changes in pH of ECF adversely affect nerve cell functions and wreck havoc with enzyme activity of all cells
38
Why does h20/salt concentration need to be maintained?
Relative conc of h20 and salts influences how much watr enters or leaves cells. must be maintained as cells don't function normally when they are swollen or shrunken
39
Why do electrolytes need to be maintained?
Some perform vital functions for example the rhythmic beating of the heart depends on a relatively constant concentration of K+ ions in the ECF
40
Why does volume and pressure need to be maintained?
The plasma must be maintained at adequate volumes to ensure bodywide distribution. blood pressure must be maintained for bodywide distribution.
41
What happens if the temperature is too high?
The structural and enzymatic proteins of cells are impaired or destroyed
42
What happens if the temperature is too low?
The cells slow down
43
What does the circulatory system consist of?
The heart, the blood vessels and the blood
44
What is the circulatory system?
A transport system
45
What does the circulatory system do?
Carries materials from one part of the body to the other - transports nutrients, o2, co2, wastes electrolytes and hormones
46
Homeostatic control mechanisms may be intrinsic or...
extrinsic
47
What is an intrinsic control mechanism?
It is a local, inherent in an organ control mechanism
| intrinsic - within a local area/organ
48
Give an example of an intrinsic control mechanism in action
exercising skeletal muscle requires o2 to generate energy to support its contractile activity. the o2 conc within the muscle falls. local chemical change acts directly on the smooth muscle in walls of the blood vessels that supply the exercising muscle. smooth muscle relax - vessels dilate. increase blood flow, increase o2. local mechanism maintains optimal level of o2 in surrounding fluid.
49
What is an extrinsic control system?
Extrinsic means outside of
| Initiated outside an organ to alter its activity
50
Give an example of an extrinsic control mechanism in action
To control blood pressure, the nervous system acts on the heart and blood vessels
51
What are extrinsic/systemic control systems mediated by?
The nervous and endocrine systems
52
Homeostatic control mechanisms operate on a principle of...
negative feedback
53
What is the negative feedback system
detection of a change away from a set point
initiates mechanisms to correct situation
shuts itself off
54
why is it called a negative feedback system?
because it drives the variable in the opposite direction of the initial change
55
What is the overall goal for a negative feedback system to achieve?
In negative feedback, a control systems output is regulated to resist change so that the controlled variable is kept at a relatively set point
56
Deviation in controlled variable detected by
the sensor
57
the sensor informs the
integrator
58
the integrator sends instructions to the
effector
59
the effector brings about a
compensatory response
60
the compensatory response results in
the controlled variable to be restored to normal
61
the negative feedback shuts off the system that was responsible for
bringing about the response
62
the negative feedback system relieves
the deviation in the controlled variable
63
Explain the seven steps involved in the general negative feedback loop
1. deviation in controlled variable detected by
2. sensor which informs the
3. integrator which sends instructions to
4. the effector(s) which brings about a
5. compensatory response resulting in the
6. controlled variable being restored to normal
7. the negative feedback shuts off system responsible for the response and relieves the deviation in the controlled variable
64
Sometimes the body temperature falls below a set point, what is this detected by?
Temperature monitoring nerve cells
65
The temperature monitoring nerve cells inform
The temperature control center
66
The temperature control centre sends instructions to
the skeletal muscles and other effectors
67
the effectors bring about
an increased heat production through shivering and other means
68
An increasing in shivering results in an
increase in body temperature
69
Why is positive feedback in the body rare
because the major goal of the body is to maintain stable homeostatic conditions
70
What is positive feedback?
With positive feedback, the output enhances or amplifies a change so that the controlled variable continues to move in the direction of the initial change
71
Give an example of positive feedback in the human body
Paturation AKA CHILDBIRTH
72
During childbirth, the fetus changes position which puts
pressure on the cervix
73
the pressure on the cervix during childbirth sends impulses to the
brain
74
The detection of impulses by the brain during childbirth cause
oxytocin to be released
75
when oxytocin is released the uterus
contracts
76
An increased contraction in the uterus
causes more pressure on the cervix
77
More pressure on the cervix as a result of contractions are detected by
stretch sensitive cells
78
Stretch sensitive cells detecting more contractions results in
more oxytocin being released and stronger uterine contractions
79
When does the positive feedback loop in parturition stop?
When the fetus is expelled there is no more stimulus on the stretch sensitive cells and therefore the loop is broken due to the stimulus being removed
80
According to the first law of thermodynamics...
energy can neither be created or destroyed. energy input is equal to energy output
81
What is the energy input?
The energy ingested in food constitutes energy input to the body
82
What happens to ingested food?
Energy is harnessed and used for biological work or stored
83
What are two categories of energy output?
external work and internal work
84
What is external work
energy expended by skeletal muscles - moving external objects
85
What is internal work
all other forms of biological energy expenditure
86
Give two examples of internal work
Skeletal muscle activity - posture and shivering
| energy expending activities required to sustain life - pumping blood
87
most food energy is converted to
heat
88
What is the metabolic rate?
The rate at which energy is expended by the body during both external and internal work is known as the metabolic rate
89
Most of the body's energy expenditure eventually appears as
heat
90
What is the metabolic rate experessed as?
heat production per hour (kcal/hr)
91
list seven factors that influence metabolic rate
```
- muscular activity
food intake
shivering
anxiety
fasting an malnutrition
fever
hormones
```
92
What is a factor that decreases the metabolic rate
fasting and malnutrition as the body is trying to conserve the energy
93
What is the basal metabolic rate
an index of metabolism under standardised conditions - minimal waking rate of internal energy expenditure
94
What are the standardised basal conditions?
```
awake
relaxed and rested for at least 30 mins
physically and mentally relaxed and rested
supine - lying down
warm - 20-25 degrees
fasting for 8/12 hours
```
95
what is the BMR for most people
20-25 kcal per body weight a day
96
How can the BMR be measured?
measured by direct or indirect calorimetry
97
indirect calorimetry is practical and less
costly
98
what is measured in indirect calorimetry?
The o2 uptake per unit of time
99
How do BMR measurements work?
They are based on the fact that there is a direct relationship between oxygen consumed and heat produced
100
Why must an energy equivalent value for complete oxidation of food be calculated when using BMR measurements?
Because different types of food use different amounts of oxygen to produce the energy
101
Does age increase or decrease BMR?
Decreases BMR, the bmr is high in children and lowers with age
102
Which gender has a lower BMR
females
103
The bmr is higher or lower in obese people?
Higher
104
Taller people have a ____ bmr
higher
105
sleep increases or decreases bmr?
decreases
106
As thyroid hormone increases, the BMR
increases
