Physiology Flashcards
(122 cards)
1
Q
What do membranes do?
A
Control exit and entry of waste products, they are selectively permeable.
-Maintain ion concentration gradients and participate in the joining of cells
2
Q
What is the plasma membrane?
A
- Phospholipid bilayer
- Cholesterol
- Proteins
- Carbohydrates
3
Q
What does cholesterol add to plasma membrane?
A
Fluidity and stability
-Stiffens the membrane
4
Q
3 types of proteins in plasma membrane?
A
Integral
Transmembrane
Peripheral
5
Q
Where are integral proteins in membrane?
A
Embedded in bilayer
-Receptors
6
Q
What are names of transmembrane proteins and where are they?
A
Transporters/channels
-Extend through membrane
7
Q
What is different about peripheral proteins compared to transmembrane and integral?
A
They do not penetrate the membrane
8
Q
What makes up the glycocalyx?
A
Glycoproteins
Glycolipids
9
Q
Functions of lipid bilayer?
A
Basic structure of membrane
Hydrophobic interior serves as a barrier
Responsible for fluidity
10
Q
Function of carrier/transport proteins?
A
Span the membrane and are substrate specific
11
Q
Where are docking marker acceptors?
A
Inner membrane surface
12
Q
How do docking membrane acceptors work?
A
Interact with secretory vesicles leading to exocytosis of vesicle contents
13
Q
How do receptor proteins work?
A
Bind specific molecules - lock & key
14
Q
Types of cell adhesion molecules (proteins)?
A
Cadherins
Integrins
15
Q
What do cadherins do? And what are they?
A
Hold cells within tissues together
Cell adhesion molecules
16
Q
What do integrins do?
A
Span membrane acting as a link between extra and intra-cellular environments
17
Q
2 Functions of carbohydrates?
A
- Serve as self identity markers enabling cells to identify and interact with one another (different cell types have different markers)
- Role in tissue growth
18
Q
3 types of specialized cell junctions?
A
Gap junctions
Tight Junctions
Desmosomes
19
Q
Desmosomes?
A
Adhering junctions that anchor cells together
20
Q
Tight junctions?
A
Join lateral edges of epithelial cells near luminal/apical membrane
21
Q
Gap junctions?
A
Communicating junctions that allow movement of charge carrying ions and small molecules between 2 adjacent cells
22
Q
What does Fick’s law of diffusion relate to?
A
- Magnitude of conc gradient
- SA of the membrane diffusion is taking place across
- Lipid solubility of substance
- Molecular weight of substance
- Distance which diffusion must take place across
23
Q
What is an electrochemical gradient?
A
Where an electrical and a concentration (chemical) gradient may be acting on a particular ion at the same time
24
Q
Osmosis?
A
Net diffusion of water down a concentration gradient
25
What are water channels called?
Aquaporins
26
Osmolarity?
Concentration of osmotically active particles in a solution
27
What is osmolarity measured in?
Osmoles/Litre
28
Osmolarity of body fluids?
~300mOsm
29
Tonicity?
Effect a solution has on cell volume
30
Units of tonicity?
NO UNITS
31
What is carrier-mediated transport?
Substance binds to specific carrier and undergoes transformational change to transport substance
32
What is saturation another term for?
Transport maximum (Tm)
33
Fact file of facilitated diffusion?
- Energy?
- Mediated?
- Gradient direction
No energy required
- Carrier mediated
- From high to low conc
34
Active transport fact file?
Energy?
Gradient?
Types?
-Energy required
-Low concentration to high concentration
-Primary= energy directly required
Secondary= Energy required but not used directly
35
Secondary active transport energy?
- Energy required but not used directly
| - It is stored in the form of an ion concentration gradient (usually Na+)
36
Mechanisms of secondary active transport?
2 mechanisms
- Symport- contransport= solute and Na+ move in the same direction
- Antiport - exchange/countertransport = Solute and Na+ move in opposite directions
37
What is K+/Na+ATPase used in? Where is it?
Primary active transport
| Plasma membrane of all cells
38
Ratio of NA:K movement in primary AT?
3 Na out
| 2 K in
39
3 important roles of Na+/K+ATPase?
- Establish Na/K concentration gradients across plasma membrane
- Regulate cell volume by controlling concentration of solutes inside the cell
- Energy used to drive the pump indirectly serves as energy source for secondary AT
40
Types of vesicular transport?
Endocytosis
| Exocytosis
41
Endocytosis?
Membrane pinches off to engulf substance
42
Exocytosis?
Vesicle fuses with membrane, releasing contents to ECF
43
What is Em? Units?
Membrane potential - separation of opposite charges across membrane
-mV
44
Concentration gradient direction for K+?
Outward
45
Concentration gradient for Na+?
Inward
46
Electrical gradient for K+/Na+?
Both positively charged so the EG for both will be towards the negatively charged side of the membrane
47
Equilibrium potential for K+?
When concentration and electrical gradients balance eachother
48
Membrane potential at Ek?
-90mV
49
Membrane potential for Na+?
ENa+ +61mV
50
Nernst equation?
Eion=
| 61Log10 [ion]0/[ion]i
51
Resting membrane potential for a typical nerve cell?
-70mV
52
What is the Nernst equation used for?
To find cell potential under non-standard conditions
53
Why is Em of nerve cell close but not identical to Ek?
Slight inward leak of Na+ into the cell, K+ gradient is most important factor here
54
Goldman-Hodgkin-Katz equation
Em= 61Log10 Pk+[K+]o + PNa+ [Na+]o
___________________________________
Pk+[K+]i + PNa+ [Na+]i
55
What is the Goldman Hodgkin Katz equation used for?
Calculating overall membrane potential
56
What does P stand for in Goldman Hodgkin Katz equation?
Relative permeability
57
Hyperpolarization?
More negative
58
Depolarisation?
More positive
59
Which hormones control glucose in post absorptive and absorptive states?
Insulin
| Glucagon (pancreas)
60
Which hormone controls glucose in emergencies?
Adrenalin (adrenal gland)
61
Which hormones control glucose during starvation?
```
Cortisol (Adrenal)
Growth hormone (pituitary)
```
62
Types of pancreatic islets of langerhan?
Alpha
Beta
Delta
63
What do alpha pancreatic islets of langerhan produce?
Glucagon
64
What do beta pancreatic islets of langerhans produce?
Insulin
65
What do delta pancreatic islets of langerhan produce?
Somatostatin
66
What are pancreatic islets of langerhan located in?
Endocrine glands
67
```
What happens to levels of
-Glucose
-Insulin
-Glucagon
in absorptive state?
```
- Glucose rises
- Insulin rises
- Glucagon falls
68
Which process does insulin favour?
Anabolism
69
What is converted to what by insulin?
Glucose -> Glycogen
Fatty acids-> Triglycerides
Amino acids -> protein
70
What is the hormone of the fed state?
Insulin
71
Effects of insulin?
- Lowers glucose by stimulating uptake from blood and activating liver enzymes
- Promoting secretion= increased glucose= increased parasympathetic activity
- Inhibiting secretion = decreased glucose = increased sympathetic activity
72
Which process does glucagon favour?
Catabolism
73
What is converted to what by glucagons presence?
Glycogen -> Glucose
| Triglycerides-> Fatty acids
74
What is glucagon the hormone of?
The hungry state
75
Effects of glucagon?
Raises glucose by increasing glycogenesis, inhibiting liver glycogen synthesis, promoting liver gluconeogenisis, lipolysis
76
What happens in type 1 diabetes?
Little/no insulin release
-Defect in beta cells
Insulin injections required
-Early onset
77
Stimulation of release of glucagon?
Decreased blood glucose
Amino acids
Sympathetic nerve activity
78
Stimulation of inhibition of release of glucagon?
Raised blood glucose
| Insulin
79
Type 2 diabetes?
Insulin secretion MAY be normal
-Defect in insulin sensitivity
-Diet/exercise/oral drugs
ADULT onset
80
Adrenaline raises glucose. True or false?
True
- Stimulates gluconeogenesis
- Stimulates glycogenolysis
81
When is adrenaline released?
During short term emergencies
82
What does cortisol do to glucose levels?
Raises them
83
What processes does cortisol stimulate?
-Protein catabolism
-Gluconeogenesis
-Lipolysis
-
84
Where is growth hormone secreted from?
Anterior lobe of pituitary
85
In response to ________, growth hormone does 3 things
1.
2.
3.?
Starvation
1. Decreases glucose uptake by muscle
2. Mobilises glucose form liver
3. Promotes lipolysis in fat cells
86
Where are baroreceptors located?
Aortic arch
| Carotid sinus
87
Process of baroreceptor activation?
1. Sensitive to stretch
| 2. Firing rate increases when MAP increases (decreases when MAP decreases)
88
What happens to baroreceptor firing if high blood pressure is sustained?
Firing decreases
| They only respond to acute changes
89
Definition of blood pressure?
The outwards (hydrostatic) pressure exerted by the blood on blood vessel walls
90
Systolic pressure?
When the heart is contracting (normally <140mmHg)
91
Diastolic pressure?
When the heart is relaxed (normally <90mmHg)
92
MAP?
The average arterial blood pressure during a single cardiac cycle
93
What is the average MAP range?
70-105mmHg
94
MAP equations when you have diastolic and systolic?
```
MAP = [(2x diastolic) + systolic]/3
MAP = DBP + 1/3 difference between SBP/DBP
```
95
MAP equations?
MAP = Cardiac output (CO) x Total peripheral Resistance (TPR)
96
CO equation?
CO = stroke volume (SV) x Heart rate (HR)
97
How can MAP be regulated?
By regulating
- HR
- SV
- TPR
98
Which vessels control resistance?
Arterioles
99
Tissue?
Group of cells with similar structure and specialized function
100
Organs?
Two or more types of primary tissues which perform a particular function
101
General idea of how homeostasis works?
- Sense deviations from normal
- Integrate this information
- Make appropriate adjustments to restore controlled variable to a desired variable
102
Intrinsic controls?
Local controls inherent in an organ
103
Extrinsic controls?
Regulatory mechanisms initiated outside an organ
| Accomplished by nervous and endocrine systems
104
Feedforward?
Responses made in anticipation of change
105
Feedback?
Responses made after a change has occurred
106
What does positive feedback do?
Amplifies a change
107
What temperature is the body homeostatically maintained at?
37.8 celcius
108
What does having normothermia optimise?
Cellular metabolism
| Cellular function
109
What temperature range should your ear drum have?
35.5-37.5)
110
What temperature range should rectal passage have?
(36.7- 37.5)
111
Which hormones can increase metabolic heat?
Adrenaline, noradrenaline, thyroxine
112
What is basal metabolic rate?
Basic level of heat production
113
What is conduction dependent on and what is it?
Transfer of heat between objects
| dependent upon temperature gradient and thermal conductivity
114
Passive evaporation is called?
Sweating - controlled by sympathetic nervous system
115
Maintaining core temperature negative feedback mechanism?
- Sensor detects change in controlled variable
- Sends signal to hypothalamus
- Effectors (skin muscles, arterioles, sweat glands) triggered to respond and restore variable to normal
116
What is the hypothalamus?
Small area in the brain
| Body's thermostat
117
What happens in the posterior hypothalamic centre?
Controls cold
- Vasoconstriction
- Increased muscle tone
- Shivering
118
What controls warmth in the hypothalamus?
Anterior hypothalamic centre
- Vasodilation
- Sweating
- Decreased muscle tone
119
Mechanism of fever?
- Macrophages release chemicals which act as endogenous pyrogen
- Stimulates hypothalamus to release prostaglandins
- Resets thermostat to higher temp
- Hypothalamus initiated mechanism to heat body (cold response)
- Thermostat reset to normal if pyrogen release is reduced/stopped
120
What temperature is fever?
38-40 degrees celcius
121
Hyperthermia?
>40 degrees celcius
122
Hypothermia?
<36 degrees or below
