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134 Cards in this Set
- Front
- Back
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Peripheral Nervous System (PNS) |
Cranial nerve & spinal nerves Communication line between the CNS & body |
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Sensory (afferent) nerves |
Somatic & visceral nerves Conducts impulses from receptors to CNS |
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Motor (efferent) nerves |
Motor nerves Conducts action potentials from CNS to effectors (muscles & glands) |
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Sympathetic Division |
Mobilises body systems for activity (i.e. flight or fight) |
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Autonamic nervous system (ANS) |
Visceral motor (involuntary) Conducts action potentials from CNS to cardiac muscles, smooth muscle & glands |
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Somatic Nervous System |
Somatic motor (voluntarily) Conducts action potential from the CNS to skeletal muscle |
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Parasympathetic Division |
Conserves energy Promotes digestion (rest & repair) |
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How does ANS function? |
Sympathetic - noradreline (NA) acting on adrenoceptors Parasympathetic - acetylcholine (Ach) acting on muscarinic Ach receptors |
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Ganglia neurotransmitter |
Ach for both symp. & parasymp. ganglia acting on nicotinic Ach receptors |
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Localisation of Ganglia |
Symp: close to spinal cord Parasymp: close or within target organs |
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The neurotransmitter at all autonamic ganglia & parasymp. neuroeffector junctions is |
Acetylcholine |
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The neurotransmitter at all symp. neuroeffector junctions is |
Norepinephrine |
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Synthesis of noradrenaline & adrenaline |
Tyrosine ---> DOPA ---> Dopamine ---> Noradrenaline (synthesis stops here for symp. nerve endings) ---> Adrenaline |
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Where is Tyrosine derived from? |
From dietary proteins |
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Where is DOPA derived from? |
In cytoplasm of nerve ending |
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Where is Dopamine derived from? |
Accumulated in storage granules |
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Enzyme responsible for converting Tyrosine into DOPA |
Tyrosine Hydroxylase |
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Enzyme responsible for converting DOPA into Dopamine |
Dopa Decarboxylase |
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Enzyme responsible for converting Dopamine into Noradrenaline |
Dopamine B-Hydroxylase |
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Enzyme responsible for converting Noradrenaline into Adrenaline |
Phenylethandomine N-Methyl Transferase |
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Where is Adrenaline derived from? |
Adrenal medulla only |
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Function of Sympathetic Division |
Maintain the normal functioning of double innervated autonomic effectors by opposing the effects of parasym. impulses (e.g. slowing heart & weakening heart beat) |
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Function of Sympathetic Impulses |
Maintain the heartbeat's normal rate & strength. |
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Only sympathetic fibres |
innervate the smooth muscle in blood vessel walls |
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Inactivation of Catecholamines |
1) Uptake 2) Enzymatic Inactivation 3) Diffusion |
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Uptake 1 |
Into nerve ending (neuronal uptake) specific for noradrenaline rapid & efficient major route 90% of released noradrenaline |
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Uptake 2 |
Into other cells & tissues (extra-neuronal uptake) less specific - Adrenaline removed, faster than noradrenaline important at synapse when uptake 1 impaired |
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MAO (Monoamine oxidase) |
In nerve ending - associated with mitochondria In extracellular fluid |
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COMT (Catechal-o-methyl transferase) |
In extracellular fluid |
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Under which conditions do parasympathetic systems predominate? |
Non-stressful & the in-between times of "rest & repair) |
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Function of Parasympathetic System |
Slows heartbeat Promotes digestion Gland secretion |
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Autonomic Effectors (Glands) |
Sweat Lacrimal Digestive Liver Adrenal Medulla |
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a-Adrenoreceptors |
a1 (postsynaptic at sympathetic neuroeffector synapses) a2 (presynaptic at sympathetic neuroeffector synapses) |
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B-Adrenoreceptors |
B1 (heart, intestinal smooth muscle) B2 (broncheal, vascular & uterine smooth muscle) |
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When is acetylcholine nicotinic/muscarinic? |
Nicotinic (in sympathetic & parasympathetic ganglia)
Muscarinic (parasympathetic neuroeffector synapses) |
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What are Sympathomimetics? |
Drugs that mimic the actions of norepinephrine & epinephrine |
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B2 Adrenoreceptor Agonist |
agonists cause bronchial dilation & are used in treatment of asthma |
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B1 Adrenoreceptor Agonist |
Agonists are sometimes used to stimulate the force of heart contraction |
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a1 Adrenoreceptor Agonist |
Agonists are used to dilute the pupil |
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a2 Adrenoreceptor Agonist |
agonists are centrally acting hypotensive drugs |
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a-Adrenoreceptor Antagonist |
a1- Adrenoreceptor blockers reduce arteriolar & venous tone |
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B-Adrenoreceptor Antagonist |
B1- Adrenoreceptor blockers reduce rate & force of contraction of heart rate with less effect on blood vessels & bronchioles |
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Sympathetic Innervation |
Thoracolumbar |
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Parasympathetic Innervation |
Craniosacral |
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Cardiovascular System |
Provides rapid transport of nutrients to the tissues in the body & allow rapid removal of waste products |
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Cardiovascular System Function |
Transport & secret hormones (e.g. atrial natriuretic peptide) Host defence, transport immune cells & antigens & other mediators (e.g.antibody) Temperature regulation |
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3 Components of CVS |
The Heart Blood Blood vessels or vascular system |
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Precardium |
Heart is located within a fluid filled membrane sac |
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Epicardium |
Inner lining of the pericardium is continuous with the covering of the heart itself |
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Myocardium |
Walls of the heart are composed of cardiac muscle cells |
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Endocardium |
Inner surface of walls that is in contact with blood |
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Myocardium is supplied with blood by: |
Coronary Arteries Coronary Blood Flow |
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What are cardiac muscle walls joined together by & why? |
Gap junctions to allow for the spread of excitation from one cell to another |
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Conducting System |
Myocardium contains specialised cells that constitute the Conducting System & are essential for heart excitation |
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2 Phases of Cardiac Cycle |
Contractile Phase (systole) Relaxation (filling) phase (diastole) |
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What does the alternation between contraction & relaxation produce? |
The differences in pressure which push the blood into the heart chambers & the circulation |
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Events leading to Cardiac Contraction |
1)Depolarisation of plasma membrane 2)Opening of voltage-sensitive Ca2+ channels 3)Flow of Ca2+ into cell (Ca2+ release from sarcoplasmic reticulum) 4)Rise in cytosolic Ca2+ concentration 5)CONTRACTION |
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Sino - atrial node |
Pacemaker |
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After electrical excitation |
Contraction |
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Atrioventricular Node |
Tactical Pause |
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Ventricular conducting fibers |
Freeways |
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Ventricular Myocardium |
Surface Roads |
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Intrinsic Conduction System |
Originates at the sinoatral (SA) node |
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Define Action Potential |
A transient depolarization of the cell membrane Initiated when membrane is depolarized Occur spontaneously (in nodal cells) Transmission from adjacent myocytes through gap junctions |
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The electrical potential across a plasma membrane is determined by 2 main factors: |
Distribution of ions across the membrane Selectively permeability of cell membrane |
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The Resting Membrane Potential |
K+ (potassium) ions are the major determinants of resting membrane potentials The resting membrane is only slightly permeable to Na+ (sodium) |
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Refractory Periods |
Absolute refractory period (ARP) - ~250ms in myocytes Relative refractory period (RRP) |
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(CHRONOTROPIC CONTROL) Sympathetic Fibres - Noradrenaline |
B1 Receptors increasing the permeability of nodal cell plasma membrane to Na+ & Ca2+ |
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(CHRONOTROPIC CONTROL)Parasympathetic - Acetylcholine |
M2 Receptors, increasing the permeability to K+ & decreasing the Na+ & Ca2+ permeability |
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What is Pacemaker Rate affected by? |
Temperature. This is why heart rate increases when a person has a fever |
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What does the slope of phase 4 depolarisation in SA nodal cells determine? |
Heart Rate |
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Heart rate at rest |
50 to 70 > 200 at max. exercise |
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Stroke Volume (SV) |
Volume of blood pumped per contraction Is only 50% end-diastolic volume at rest |
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End-Diastolic Volume (EDV) |
Volume of blood in ventrical after contraction |
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End-Systolic Volume (ESV) |
Volume of blood in ventricle after contraction |
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How to calculate Stroke Volume (SV) |
End-Diastolic Volume (EDV) - End-Systolic Volume (ESV) |
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What increases Stroke Volume (SV)? |
Expelling end-diastolic volume -e.g. catecholamines increasing force of contraction |
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Regulation of Arterial Blood Pressure |
Baroreceptor reflex Chemoreceptor reflex Cardiopulmonary reflexes (CO/resp rate) |
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Hormonal Control (long term) |
Vasopressin Angiotensin II Aldosterone Atrial natrineretic peptide (ANP) |
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How is Arterial Blood Pressure calculated? |
Cardiac Output (CO) x total peripheral resistance (TPR) |
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Factors influencing Blood Pressure |
Stroke Volume, Heart Rate, Blood Viscosity, Arteriolar Diameter, Cardiac Output, Peripheral Resistance, Arterial Blood Pressure |
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Arteriolar Radius |
Symp. nerves, Noradrenaline, a1, CONSTRICT Symp. cholinergic, Nerves (skeletal muscle), Acetylcholine, Muscarinic (M3), DILATE Plasma Membrane, B2, DILATE Local Controls: PO2,PCO2,K+, Adenosine, DILATE |
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How to calculate flow of lungs |
Change in Pressure/ Resistance |
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Pressure of a gas in a mixture is called |
Partial Pressure (P) |
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Ventilation |
Exchange of air between atmosphere & alveoli by bulk flow (e.g transfer of CO2 & O2 through pulmonary & system circulation) |
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Gas exchange of O2 & CO2 between alveolar air & blood in lung capillaries by |
Diffusion |
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5L of arterial blood contains: |
15ml physically dissolved O2 remainder (985ml O2) bound to haemoglobin 4 x subunits = 4 x globin - haeme (Fe2+ binds O2) |
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Metabolically active tissue |
Lower PO2 Higher PCO2 (thus H+) Increased temperature Greater O2 unloading |
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Oxygen Transport by Haemoglobin |
Oxygen unloads from Haemoglobin to Tissue CO2 moves from tissue to blood CO2 moves from blood to alveoli |
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What does Carbonic Anhydrase (CA) in erythrocytes catalyse? |
CO2 + H2O ---> HCO3 + H+ |
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In breath (Inspiration) |
Diaphragm contracts External intercostal muscles pull ribs up & out |
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Out Breath (Expiration) |
Diaphragm relaxes & abdominal organs press upwards Lung elasticity recoils inwards |
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Maximum Inspiration |
Sternum moves up & out Diaphragm contracts more |
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Maximum Expiration |
Internal intercostal muscles pull ribs down & out Abdominal muscles compress organs & force diaphragm higher |
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Chemical Inputs that stimulate ventilation |
Arterial PO2 Production of non-CO2 acids Arterial PCO2 |
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Skeletal Muscle Control: Motor Nerves |
Muscle action potential Ca2+ rise Contraction |
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Contractile filaments |
Myosin (Thick) Actin (Thin) |
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Acetylcholine released by nerves binds |
Nicotinic Ach-receptors Acetylcholine binding opens ion channels |
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Afferent cholinergic innervation from... |
Brainstem/spinal cord |
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Neuromuscular Junction |
No inhibitory nerves Na+ influx --> end-plate potential |
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What does the Action Potential propagate? |
Across the plasma membrane into T-tubules |
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Voltage-sensor activates... |
Ryanodine Receptor on Sarcoplasmic Retiulum |
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Function of Ca2+ at Neuromuscular Function |
Ca2+ release into cytosol Ca2+ enters voltage-gated channels Ca2+ released from terminal cistemae Ca2+ binding --> myosin able to bind troponin |
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Why does Myosin head - group bind actin? |
To drive contraction |
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What does ATP hydrolysis energise/drive? |
Energises Myosin Drives: 1)Cross-bridge cycling 2)Restoration of plasma-membrane ion gradients (Na+/K+ - ATPase) 3) Removal of Ca2+ from cytosol back into sarcosplasmic reticulium (Ca2+ - ATPase) |
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Cycle of ATP binding, hydrolysis, ADP/Pi release drives... |
Ratchets myosin toward Z-line |
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Ca2+ removal from Troponin |
Restores tropomyosin blocking action |
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Ca2+ binding to Troponin |
Removes blocking action of tropomyosin |
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Resupply of ATP within the Skeletal Muscle |
Phosphorylation of ADP by Creatine Phosphate Mitochondrial Oxidative Phosphorylation Oxygen (aerobic) Glycolisis supplied by blood & catabolism of muscle glycogen |
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Whole muscle tension |
Sum of recruitment of motor units |
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Exercise decreases muscle |
ATP O2 Phospho-creative |
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Thermoregulation |
Increased peripheral blood flow & sweating Increased ATP production Increase size of muscle fibres |
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Low-Intensity: Aerobic |
Increased mitochondria Increased capillaries |
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Endurance training |
Fast-glycolytic fbres become fast-oxidative-glycolytic fibres (IIb --> IIa) |
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High-Intensity "strength - training" |
Increased diameter of fast-twitch fibres (Hypertrophy)
Increased expression of glycolytic enzymes Greater synchronisation of motor unit recruitment |
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Effect of exercise on Cardiovascular & Respiratory Systems |
Supplying O2 from lungs to skeletal muscle via increased blood flow Control body temp. by thermoregulation Increasing peripheral blood flow & sweating |
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Extremely fast change in rate of breathing
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Not due to gradual chemical changes |
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Maximal O2 Consumption |
VO2 Max = arterial O2 content - venous O2 content) x CO (cardiac output) (limiting factor = cardiac OUTPUT) |
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Increased mitochondria |
Does not affect VO2 max, BUT does increase endurance |
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Endogenous Anabolic Steroids |
Testosterone, Nandrolone, DHEA |
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Exogenous Anabolic Steroids |
Metandienone, Stanozold |
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Hormones & Hormone Modulator (Anabolic Steroids) |
Choriomic gonadotrophin --> increased testosterone production Aromatose Inhibitors --> decreased testosterone breakdown |
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Desired effects of Anabolic Steroids |
Increased muscle development Increased competitiveness & aggression |
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Growth hormone produced in children |
Somatotrophin (GH) (release stimulated by GHRH (GH-releasing factor)) |
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Desired effects of somatotropin |
Increased lean body mass Decreased fat Increased recovery/repair |
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Red Blood Cell Production |
Manually: blood doping Hormonally: erythropoietin (epoitin/EPO) - recombinant expressed glycoprotein; hypoxia-mimicking agents (argon/xenon; cobalt) but altitude training is legal |
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B-adrenergic receptor agonists |
B1-receptors on heart B2 receptors on vascular/bronchial smooth muscle |
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Bronchodilation |
Increased oxygen uptake |
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B2-specific agonists |
Salbutamol (limited concentration allowed) Terbutaline Clenbutarol |
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B1/2-specific agonists |
Epinephrine (local administration allowed) |
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B2-adrenergic Receptor Antagonists |
Propanolol Reduce tremor in precision sports (shooting, archery) |
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Stimulus (CNS) |
Ephedrine, Amphetamine, Cocaine Locomotor stimulation Increased stamina & excitement a-adenosine anatagonist Inhibits phosphodiesterase --> inc cAMP --> mimics B-stimulation |
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CNS + Peripheral Stimulant |
Cardiac & Smooth Muscle Action |
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Other Gene Doping |
Mouse Experiments (genetic mutations produced that alter muscle mass, power & endurance) Naturally occurring genetic mutations/ polymorphisms can affect physical performance |
