Physiology Flashcards
1
Q
What is physiology?
A
Physiology - Study of normal functions of the human body and the integrative mechanisms that control them
2
Q
What is a tissue?
A
Tissue: Group of cells with a similar structure and specialised function
3
Q
What is an organ?
A
Organs: made up of two or more types of primary tissue which perform a particular function
4
Q
What is a body system?
A
Body system: made up of groups of organs that perform related functions and work together to achieve a common goal
5
Q
What is homeostasis?
A
Homeostasis is the maintenance of steady states within our bodies coordinated by physiological mechanisms
6
Q
What are intrinsic controls?
A
Intrinsic controls: local controls that are inherent in an organ
7
Q
What are extrinsic controls?
A
Extrinsic controls: regulatory mechanisms initiated outside an organ, accomplished by nervous and endocrine systems
8
Q
What is a feedforward control system?
A
Feedforward control system: Responses made in anticipation of a change
9
Q
What are the 2 types of feedback systems?
A
Negative & Positive Feedback
10
Q
What is a positive feedback system?
A
Positive feedback system: amplify an initial change (after which has been detected)
11
Q
What is a negative feedback system?
A
Negative feedback system: Oppose an initial change (after which has been detected) = main homeostatic control system
12
Q
What are the 3 main parts of a negative feedback system?
A
Components:
- Sensor
- Control Centre
- Effector
13
Q
What are some examples of physiological parameters controlled by feedback systems?
A
Involved in the control of…
- Blood pressure
- Body temperature
- Blood glucose
- Blood gases conc
- Blood pH (Kidneys, CO2)
14
Q
What is blood pressure?
A
Blood pressure: Outwards hydrostatic pressure exerted by blood on blood vessel walls
15
Q
What is systemic systolic blood pressure?
A
Systemic systolic blood pressure - Pressure exerted by blood on walls of aorta and systemic arteries when heart contracts (Normal 90-120 mmHg)
16
Q
What is systemic diastolic blood pressure?
A
Systemic diastolic blood pressure - Pressure exerted by blood on walls of aorta and systemic arteries when heart relaxes (Normal 60-80 mmHg)
17
Q
What blood pressure readings is characteristic of hypertension?
A
Hypertension - 140/90 mmHg (& daytime average 135/85 mmHg)
18
Q
What is the pulse pressure?
A
Pulse pressure - Difference between systolic and diastolic blood pressure (normally 30 - 50 mmHg)
19
Q
What is the Mean Arterial Blood Pressure (MAP)?
A
Mean Arterial Blood pressure - Average arterial blood pressure during a single cardiac cycle
20
Q
What is vasomotor tone?
A
Vasomotor tone = Vascular smooth muscles are partially constricted at rest, by tonic discharge of sympathetic nerves
21
Q
What is autorhythmicity?
A
Autorhythmicity = Ability of heart to beat in absence of external stimuli
22
Q
What are the steps involved in parasympathetic regulation of MAP?
A
Parasympathetic stimulation -> Heart -> Decreased Heart Rate -> Decreased Cardiac Output -> Decreased MAP
23
Q
There are 4 pathways involved in Sympathetic regulation of MAP. These include routes through:
- The Heart
- The Arterioles
- The Veins
How does the sympathetic system affect these structures, and result in a change in MAP?
A
- Heart -> Increased Heart Rate -> Increased Cardiac Output -> Increased MAP
- Heart -> Increased Contractile Strength of Heart -> Increased Stroke Volume -> Increased Cardiac Output -> Increased MAP
- Arterioles -> Increased vasoconstriction -> Increased SVR (TPR) -> Increased MAP
- Veins -> Increased vasoconstriction -> Increased venous return -> Increased Stroke Volume -> Increased Cardiac Output -> Increased MAP
24
Q
The MAP is regulated by a negative feedback system. What are the sensors, control centre & effectors involved?
A
Sensors - Baroreceptors
Control Centre - Medulla
Effectors - Heart & Blood Vessels
25
Where are baroreceptors located?
What do they respond to?
Baroreceptors:
- In aortic arch and carotid sinus
- Baroreceptors are sensitive to stretch, they only respond to ACUTE and SUSTAINED changes in arterial blood pressure
26
What nerve is connected to the aortic baroreceptors?
What nerve is connected to the carotid baroreceptors?
Xth/ 10th/ Vagus nerve - Connected to aortic baroreceptors
Hering’s Nerve (part of IXth/ Glossopharyngeal nerve) - Connected to carotid baroreceptors
27
What is the effect of decreased arterial blood pressure on baroreceptor discharge?
How does this affect the firing of the vagus nerve & carotid sinus afferent fibres?
What is the impact of this on sympathetic stimulation?
What is the final effect on the heart and blood vessels?
Decreased arterial blood pressure:
1. Decreased Baroreceptor discharge
2. Decreased carotid sinus afferent/ vagus nerve fibres firing
& increased cardiac sympathetic efferent nerve fibre activity
& increased sympathetic vasoconstrictor nerve fibres activity
3. Increased force of contraction & increased HR
& venoconstriction (Increased venous return)
& vasoconstriction (Increased SVR)
28
What is the effect of increased arterial blood pressure on baroreceptor discharge?
How does this affect the firing of the vagus nerve & carotid sinus afferent fibres?
What is the impact of this on sympathetic stimulation?
What is the final effect on the heart and blood vessels?
Increased arterial blood pressure:
1. Increased baroreceptor discharge
2. Increased carotid sinus afferent/ vagus nerve fibres firing
& decreased cardiac sympathetic efferent nerve fibre activity
& decreased sympathetic vasoconstrictor nerve fibres activity
3. Decreased HR
& venodilation (Decreased venous return)
& vasodilation (Decreased SVR)
29
How can you exactly calculate MAP?
What are some other equations which allow you to estimate MAP?
Exact Calculation:
MAP = CO (SV x HR) x SVR
Estimation Calculations:
MAP = DBP + 1/3 (Pulse Pressure) OR
= (2(DBP) + SBP)/ 3
30
What is the normal range of MAP?
What MAP is required for perfusion to coronary arteries, brain & kidneys?
Normal range of MAP 70 - 105 mmHg
- At least 60mmHg is needed for perfusion to coronary arteries, brain & kidneys
31
What does SVR stand for?
What is it also known as?
What is SVR, and what is it regulated by?
SVR stands for Systemic Vascular Resistance.
Aka Total Peripheral Resistance.
SVR is the sum of resistance of all vasculature in systemic circulation. It is regulated by vascular smooth muscles.
32
What is the major resistance vessel?
Arterioles are major resistance vessels
33
What is Cardiac Output?
Cardiac Output (CO) = Volume blood pumped per ventricle per minute
34
What is Stroke Volume?
Stroke Volume (SV) = Volume blood pumped per ventricle per heart beat
35
What is an important group of afferent CVS nerves?
Afferent CVS nerves -> Nucleus tractus solitarius (synapse) in medulla in brain stem
36
What neurotransmitter & receptor is involved in sympathetic regulation of the Heart?
What neurotransmitter & receptor is involved in parasympathetic regulation of the Heart?
Sympathetic - Noradrenaline acts on Beta 1 adrenoceptor
Parasympathetic - Acetylcholine acts on Muscarinic Nicotinic Receptor (M2)
37
What is “core body temperature”?
Core body temperature = The temperature of the structures deep within the body
38
What is “core body temperature” homeostatically maintained at?
Core body temperature is homeostatically maintained within a narrow range/ set point at about 37.8 Degrees.
39
What is normothermia?
Normothermia = Optimum temperature for cellular metabolism & function. Shows diurnal variation.
40
What can “core body temperature” be altered by?
It can be altered by activity, emotions, exercise, exposure.
41
What does an indirect measure of body temperature involve?
Indirect estimate - E.g Infrared Tympanic Thermometer
42
What does a direct measure of body temperature involve?
Direct estimate - E.g Digital thermometer for rectum or oesophagus
43
What is a “normal” ear drum temperature?
What about for the rectum or oesophagus?
Ear drum - 36-37.5C
Rectum or oesophagus - Slightly higher
44
What processes are involved in heat gain?
What about heat loss?
Heat gain - Basal metabolic rate, radiation, conduction, convection
Heat loss - Radiation, conduction, convection, evaporation
45
What is the basal metabolic rate?
Basal Metabolic Rate:
- Basic level of heat production
- Can be increased by hormones (NA, A, Thyroxine)
- Muscle activity - Shivering
46
What does heat loss via radiation involve?
What % of heat loss is due to radiation?
Radiation
- Emission of heat energy as EM radiation
- 1/2 body heat loss
47
What does conduction involve?
Conduction:
- Transfer of heat between objects in contact (warmer -> cooler)
- Depends on temperature gradient & thermal conductivity
48
What does convection involve?
Convection:
- Transfer of heat energy by air or water current, combines with conduction.
- Air next to skin is warmed by conduction, warmed air is less dense and will rise while cooler air moves next to the skin
- Wind/fan increases conduction-convection, air trapping clothing does decreases conduction-convection
49
What does evaporation involve?
What are the 2 types?
Evaporation:
- Passive: Water passively diffuses from the surface of the skin and the linings of the respiratory airways. Occurs continuously, uncontrolled
- Active: Sweating controlled by SNS, relative to humidity
50
What are the sensors involved in negative feedback control of body temperature?
Sensors:
- Central thermoreceptors - Hypothalamus, abdominal organs…
- Peripheral thermoreceptors - Skin
51
What control centre is involved in negative feedback control of body temperature?
Control centre - Hypothalamus:
- Hormonal & neural controls
52
What region of the hypothalamus is activated by the cold?
What region of the hypothalamus is activated by warmth?
Posterior hypothalamic centre = activated by cold
Anterior hypothalamic centre = activated by warmth
53
What effectors are involved in negative feedback control of the hypothalamus?
Effectors:
- Skeletal muscles, skin arterioles, sweat glands
- Triggered to respond and restore variable to normal
54
What is involved in the response to cold exposure?
Response to Cold Exposure:
- Posterior hypothalamus activated
- Skin arterioles:
- Vasoconstriction -> Decreased heat loss
- Skeletal muscles:
- Increased tone, shivering, voluntary movement -> increased heat production
55
What is involved in the response to heat exposure?
Response to heat exposure:
- Anterior hypothalamus activated
- Skin arterioles:
- Vasodilation -> increased heat loss
- Sweat glands:
- Evaporation -> increased heat loss
- Skeletal muscle:
- Decreased tone, decreased voluntary movement -> decreased heat production
56
What temperature characterises hyperthermia?
What temperature characterises a fever?
What temperature characterises hypothermia?
Hyperthermia - 40C above
Fever - 38-40C
Hypothermia - Below 35C
57
What does hyperthermia involve?
Extreme uncontrolled increase in body temperature (due to failure of heat regulating mechanisms).
58
What does hypothermia involve?
Hypothermia = Drop in body temperature below that required for cellular metabolism and function
59
What are the steps by which the set point of temperature is raised during fever?
Raising the set point during a fever:
1. Macrophages release chemicals which act as an endogenous pyrogen
2. Stimulates hypothalamus to release prostaglandins
3. This ‘resets’ the thermostat to a higher temperature
4. Hypothalamus initiates mechanism to heat body - cold response
5. Thermostat reset to normal if pyrogen release reduced/ stopped
60
What are the effects of overheating?
Overheating = Protein desaturation, nerve malfunction -> convulsions & death
61
What are the 5 common clinical vital signs?
Common clinical vital signs:
- Pulse HR - 60-100 beats/min
- Blood Pressure - 90-120/60-80 mmHg
- Respiratory Rate - 12-20 breaths/min
- O2 saturation - 96% or above
- Consciousness - AVPU
62
Hypothalamus has neural connections to…
Hypothalamus has neural connections to lambic system, cerebral cortex, motor neurons of skeletal muscles and the SNS
63
What is the effect of blood loss on:
- Blood Pressure
- Stroke Volume
- Oxygen getting to the brain
Blood loss…
- Decreased bp => Dizziness
- Decreased SV => Weak pulse & decreased CO
- HR increases to try and compensate
- Lack of oxygen to brain
- Lungs try and overcompensate => breathlessness
64
What is the effect of vasoconstriction on:
- Blood flow to skin
- Heat loss from blood vessels
- Blood pressure
Vasoconstriction:
- Less blood flow to the skin/surface => pale
- Less heat loss from blood vessels in skin => cold & clammy
- Increased blood pressure
65
What is involved in the Examination & Treatment of shortness of breath?
Shortness of breath: Examination & Treatment
- Physiological measurements - Temp, pulse, blood pressure, oxygen sat., respiratory rate
- Physiological examinations - Blood glucose & ECG
- Management - Oxygen
66
What are the steps involved in the care of a patient, ranging from Primary survey to Management of condition?
ABCDE -> History -> Examination -> Investigations -> Diagnosis -> Management
67
What are some functions of the cell membrane?
Functions of the Cell Membrane:
- Acts as a boundary between intracellular and extracellular solutions
- Selectively permeable to entry of nutrients and exit of waste and secretory molecules
- Maintains ion conc. across membrane
- Helps join cells together
- Allows cells to respond to changes in extracellular environment
- Variation can be the cause of functional differences
- Important for homeostasis
68
What is a phospholipid?
Phospholipids:
- Two fatty acid tails (hydrophobic)
- Glycerol backbone
- Phosphate head group which has smaller molecule attached (hydrophilic)
69
What is the effect of temperature on the phospholipids of the cell membrane?
Increased temp => increased movement of phospholipids in bilayer
70
What determines the permeability of the cell membrane to uncharged, hydrophobic molecules?
Determining factors:
- Thickness of layer - Fatty acid tail length
- How densely packed phospholipids are - composition of head groups
71
What are 3 common small groups which can bind to phospholipids in the cell membrane?
Common small groups:
- Inositol => Phosphatidylinositol
- Serine => Phosphatidylserine
- Choline => Phosphatidylcholine
72
What is a sphingomyelin?
Choline (& sphingosine for one fatty acid) => sphingomyelin
73
What is a galactocerebroside?
Galactose (& sphingosine for one fatty acid) => galactocerebroside
74
What is the role of cholesterol in the cell membrane?
Cholesterol:
- Interacts with adjacent phospholipid molecules
- Aid in stiffening/ Rigidity
75
What are the 4 classes of membrane proteins?
Classes of membrane proteins:
- Integral - bound to phospholipid bilayer
- Integral - Alpha helical, multiple domains, transmembrane
- Peripheral - Linked directly to fatty acids
- Peripheral - Linked to phospholipids via oligosaccharides
76
What are the 5 main functions of integral proteins?
Integral Protein Function:
- Ligand binding receptors
- Adhesion molecules
- Physical contact with EC matrix or neighbouring cells
- Regulation of cell shape, growth & adaptability
- Transport
- Pores & channels - Ungated or gated, water & ions
- Carriers - Facilitate transport or coupling
- Pumps - Active transport, ATP hydrolysis
- Enzymes e.g carbonic anhydrase
- Intracellular signalling e.g GTP-binding proteins, kinases
77
What are docking marker proteins?
Docking marker proteins:
- On intracellular surface
- Interaction with secretory vesicles
- Allows exocytosis
78
Where are membrane carbohydrates located?
What layer do they form?
What might they be bound to?
What is two of their roles?
Membrane carbohydrates:
- On outer surface
- Form layer referred to as the glycocalyx
- Bound to membrane proteins (& sometimes lipids)
- Glycoproteins & glycolipids
- Act as identity markers (allow identification & interaction)
- Role in tissue growth - Ensuring don’t overgrow
79
What does permeability (of the membrane) without assistance depend on?
Permeability without assistance depends on solute solubility & size
80
What are 2 driving forces of molecules across the membrane?
Driving forces:
- Concentration gradient
- Electrical gradient
Electrochemical gradient (for ion solutes)
81
What does unassisted/ passive movement of molecules across the membrane involve?
Unassisted/ Passive:
- Simple diffusion - Down conc gradient
- Ion Channels - Down electrical gradient
- Osmosis
82
What does assisted/ selective transport of molecules across the membrane involve?
Assisted/ Selective transport:
- Carrier mediated transport
- Active Transport
- Facilitated diffusion
- Vesicular transport
83
What is diffusion?
Diffusion:
- Down a conc gradient or an electrical gradient
- May or may not be facilitated
84
Fick’s Law of Diffusion states factors which influence net rate of diffusion across membrane, what does this include?
Factors which affect rate of diffusion across membrane:
- Magnitude of conc gradient (proportional)
- Surface area of membrane (proportional)
- Lipid solubility (proportional)
- Molecular weight of substance (disproportional)
- Distance which has to be diffused (disproportional)
85
What does osmosis involve?
Osmosis:
- Water diffusion down conc gradient
- Through aquaporins (water channels)
86
What is “osmolarity”?
Osmolarity - Conc of osmotically active particles present in solution. Measured in osmoles, body fluids around 300mOsm/l.
87
What is “tonicity”?
Tonicity = Effect solution has on cell volume
88
What is the effect of placing a cell in an isotonic solution?
What is the effect of placing a cell in a hypotonic solution?
What is the effect of placing a cell in a hypertonic solution?
No net flow - Isotonic
Increase in cell volume, water into cell - Hypotonic
Decrease in cell volume, water out cell - Hypertonic
89
What are 3 important characteristics of carrier mediated transport?
3 important characteristics:
- Specificity
- Saturation
- Competition
90
What does primary active transport involve?
What does secondary active transport involve?
Primary - Requires hydrolysis of ATP e.g exit of Ca2+ in nerve terminals
Secondary - Indirect energy, from ion conc gradient e.g Na+
91
What does Symport Transport involve?
What does Antiport Transport involve?
- Symport (co transport) e.g Glucose absorption in enterocytes
- Antiport (exchange) e.g Na+ & H+ transport, intracellular pH regulation
92
What does the Na/K Pump involve?
Na/K Pump:
- 3 Na+ out, 2 K+ in
- Primary Active Transporter
- Creates ion gradients for secondary transport
93
What are 3 roles of the Na/K Pump?
3 roles of Na/K Pump:
1. Establish Na+ and K+ conc gradient
2. Regulate cell volume (by controlling inside solute conc.)
3. Indirectly serves as energy for secondary transport
94
What does endocytosis involve?
What does exocytosis involve?
Endocytosis - Pinching off & engulfing substances
Exocytosis - Fusion & secreting enzymes/ proteins hormones, adding carriers, channels or receptors to membrane e.g GLUT4
95
What is the membrane potential?
Membrane potential (Em) = Difference in charge between thin layers of ECF and ICF located next to outside and inside of membrane
96
What are some examples of excitable cells?
Excitable cells - Nerve, muscle cells
97
What is an Action Potential?
Action Potential - Rapid, transient changes in membrane potential when excited
98
What is a “Rest Potential”?
Rest Potential - Constant in non-excitable cells, rest in excitable cells
99
What is the membrane potential determined by?
Membrane potential determined by…
- Differences in conc of ions across membrane & ion permeability
100
What is the permeability of the following ions, as well as their concentration intracellularly & extracellularly:
- Sodium (Na+)
- Potassium (K+)
- Large intracellular proteins (A-)
- Chloride (Cl-)
Ion Extracellular Intracellular Permeability
Na+ 150 15 1
K+ 5 150 100
A- 0 65 0
Cl- 110 7 N/A
101
What are the membranes in skeletal muscles more permeable to?
Membranes (in skeletal muscles) - 100x more permeable to K+ than Na+
102
What does E(K+) stand for?
E(K+) = Membrane potential where both potassium conc and electrical gradient are equal, no net movement (-90mV)
103
What is the value for E(Na+)?
E(Na)+ = +60mV
104
What is the nerve cell resting potential, and why is this the case?
K+ much more permeable hence more outward movement of K+ than inward movement of Na+
Hence (nerve cell) resting potential = -70mV
105
What can the Nernst Equation be used for?
It can be used to calculate the equilibrium potential of any (single) ion
106
What is the Nernst equation?
What can it be simplified to, for a monovalent cation, at 37C?
Nernst equation:
Eion = (RT/zF) ln ([ion]o/[ion]i)
Where:
R = Gas constant
T = Temperature
F = Faradays Constant
Z = Charge on ion
For a monovalent cation at 37C:
Eion = 61 log10 ([ion]o/[ion]i)
107
What is the Goldman-Hodgkin-Katz equation?
And what can it be used for?
GHK equation can be used to calculate membrane potential:
Em = 61log10 ((Pk+[K+]o + PNa+ [Na+]o)/ (Pk+[K+]i + PNa+[Na+]i))
108
What are 3 examples of cells which produce Action Potentials?
Cardiac muscle cells, skeletal muscle cells, nerve cells - Produce Action Potentials
109
What does depolarisation involve?
What does hyperpolarisation involve?
Depolarisation - Membrane potential becomes less negative (more positive into cell)
Hyperpolarisation - Membrane potential becomes more negative (more positive out of cell)
110
What is the effect of opening sodium channels?
Open sodium channels -> Influx of Na+ into cell -> Depolarisation
111
What equation allows the calculation of Na+ current?
Na+ current (INa) = Na+ conductance x driving force
This can be rewritten as:
INa = gNa (Vm - ENa)
112
What is the effect of opening potassium ion channels?
Open potassium channels -> Efflux of K+ out of cell -> Hyperpolarisation
113
What equations allows the calculation of K+ current?
K+ current (IK) = K+ conductance x driving force
This can be rewritten as:
IK = gK (Vm - EK)
114
What is a negative driving force vs positive driving force?
Negative driving force => Inward current (of +ve ions)
Positive driving force => Outward current (of +ve ions)
115
What are the 3 types of Ion Gated Channels?
Ion Gated Channel Types:
- Voltage Gated
- Ligand Gated
- Physical stimuli e.g mechanical or thermal
116
What ion gated channels are involved in the Action Potentials in neurons?
For action potentials in neurons:
- V-Gated Na+ channels
- V-Gated K+ channels
117
What steps are involved in an Action Potential?
Resting Potential -> Depolarising stimuli -> Slight depolarisation -> Meets threshold (-60mV) -> Depolarisation/upstroke (Nav opening) -> repolarisation/downstroke (Nav inactivation, Kv opening) -> Hyperpolarisation/ Undershoot
118
What is involved in an overshoot of an Action Potential?
What is involved in an undershoot of an Action Potential?
Overshoot = positive membrane potential
Undershoot = negative membrane potential below -70mV, due to delayed K+ closure
119
What are some properties of Nav & Kv channels?
- Highly Selective
- Both activated by depolarisation
- Nav rapid vs Kv
- Nav shorter vs Kv
120
What are the 3 states of Na+ channels?
3 states of Na+ channel:
- Closed State
Depolarisation
- Open state (Conducting)
Maintained depolarisation
- Inactivated state
Repolarisation & refractory period
121
What is the absolute refractory period?
Absolute refractory period - Unable to re stimulate action potential, regardless of strength of stimuli, Na+ channels in inactivated state
122
What is the relative refractory period?
Relative refractory period - Stronger than normal stimulus may elicit second action potential, mixed population of inactivated and closed channels & hyperpolarised membrane
123
With regard to an Action Potential, where on a neuron is the:
- Input Zone
- Trigger Zone
- Conducting Zone
- Output Zone
Input Zone - Dendrites, Receive signal
Trigger Zone - Axon Hillock, initiates an Action Potential
Conducting Zone - Axon, Undiminishing conduction
Output Zone - Axon Terminals, Release Neurotransmitter
124
What are the 2 nerve types?
2 nerve types:
- Myelinated - saltatory conduction
- Non myelinated - Contiguous/ passive conduction
125
What does passive/ contiguous conduction involve?
Passive/ Contiguous conduction:
- Spreads from one area to the next
126
How can the velocity of passive conduction be increased?
Velocity can be increased by:
- Increased axon diameter
- Decreased leak of current through e.g myelination/ macroglia
127
What does saltatory conduction involve?
Saltatory conduction:
- Travels from one node of ranvier to the next
128
What is myelin?
Where is it produced?
Myelin:
- Lipid, insulator
- Produced by macroglia
- Schwann cells, PNS, many surround 1 axon
- Oligodendrocytes, CNS, 1 surrounds many axons
129
What are nodes of ranvier?
Nodes of ranvier - Clusters of Voltage Gated Channels
130
What are the hormones involved in controlling glucose:
1. In absorptive and post absorptive states
2. In emergencies
3. During starvation
1. Insulin & glucagon
2. Adrenaline
3. Cortisol & Growth Hormone
131
What are the 3 types of Pancreatic Islet Cells?
Pancreatic Islets of Langerhans:
- Alpha Cells = Glucagon
- Beta Cells = Insulin
- Delta Cells = Somatostatin
132
What are some effects of insulin?
Insulin favours anabolism:
- Glucose -> Glycogen
- Fatty Acids -> Triglycerides
- Amino Acids -> Protein
It overall lowers glucose by stimulating uptake from blood and activating liver enzymes.
133
1. What promotes the secretion of insulin?
2. What inhibits the secretion of insulin?
1. Increased glucose, amino acids, parasympathetic activity, glucagon, GIP
2. Decreased glucose, increased sympathetic activity
134
What are some effects of glucagon?
Glucagon favours catabolism:
- Glycogen -> Glucose
- Triglycerides -> Fatty Acids
Glucagon overall raises glucose by increasing glycogenolysis, inhibiting liver glycogen synthesis, promoting liver gluconeogenesis, lipolysis (also in adipose tissue).
135
1. What stimulates the release of glucagon?
2. What inhibits the release of glucagon?
1. Decreased blood glucose & amino acids, increased sympathetic nerve activity
2. Raised blood glucose & insulin
136
With regard to Type 1 Diabetes Mellitus:
- When is the onset?
- What does it involve?
- What is there a defect in?
- What does treatment involve?
Type 1 Diabetes Mellitus:
- Early onset
- Little/ no insulin secretion
- Defect in beta cells
- Insulin injections required
137
With regard to Type 2 Diabetes Mellitus:
- When is the onset?
- What does it involve?
- What is there a defect in?
- What does treatment involve?
Type 2 Diabetes Mellitus:
- Adult Onset
- Insulin secretion may be normal
- Defect in insulin sensitivity
- Diet/ Exercise/ Oral Drugs
138
What are the metabolic effects of adrenaline?
Adrenaline:
- Raises glucose
- Stimulates glycogenolysis
- Stimulates gluconeogenesis
139
What are the metabolic effects of cortisol?
Cortisol:
- Raises glucose
- Stimulates protein catabolism
- Stimulates gluconeogenesis
- Stimulates lipolysis
140
What are the effects of the growth hormone, in response to starvation?
In response to starvation:
- Decreases glucose uptake by muscle
- Mobilises glucose from liver
- Promotes lipolysis in fat cells
