1. CVC send autonomic nerves both sympathetic and parasympathetic to the heart and blood vessels
2. Due to closure of the atrioventricular valves
3. Heart sounds
3.1. 'Lub'
3.1.1. Fairly loud
3.1.1.1. corresponds with start of ventricular systole
3.2. conducting system of the heart
3.2.1. Direction of impulse
3.2.1.1. Superior Vena Cava
3.2.1.2. Sinoatrial (SA) Node
3.2.1.3. Atrioventricular (AV) Node
3.2.1.4. Atrioventricular bundle (AV) bundle / bundle of His
3.2.1.5. Left Atrioventricular (LAV) bundle
3.2.1.6. network of Purkinje Fibres
3.2.2. posses the property of autorhythmicity (generates its own electrical impulses and beats independently of nervous or hormonal control)
3.2.2.1. Heart rate
3.2.2.1.1. supplied with both sympathetic and parasympathetic nerve fibres
3.2.2.1.2. Heart responds to circulation hormones eg Adrenaline and thyroxine
3.2.3. small groups of specialised neuromuscular cells in the myocardium initiate and conduct impulses
3.2.3.1. causes coordinated and synchronised contraction of the heart muscle
3.2.4. Sino atrial (SA) node
3.2.4.1. is a small mass of specialised cells that lies in the wall of the right atrium
3.2.4.2. these cells generate these regular impulses because they are electrically unstable
3.2.4.2.1. this instability leads them to discharge (depolarise) regularly
3.2.5. Atrioventricular (AV) node
3.2.5.1. is a small mass of neuromuscular tissue situated in the wall of the atria septum near the atrioventricular valves
3.2.5.2. normally merely transmits electrical signals from the atria to the ventricles
3.2.5.2.1. there is a 0.1 second delay here to pass through the ventricles
3.2.5.3. has a secondary pacemaker function
3.2.5.3.1. takes over this role if there is a problem with the SA node or with transmission of impulses from the atria
3.2.5.4. atrioventricular bundle bundle (AV bundle / bundle of HIS)
3.2.5.4.1. this is a mass of specialised fibres that originate from the AV node
3.2.5.4.2. it divides into the right and left bundle branches
3.2.5.4.3. withing the ventricular myocardium the branches break up into fine fibres called the purkinje fibres
3.2.5.4.4. these fibres transmit electrical impulses from the AV node to the apex of the myocardium where the wave of ventricular begins
3.2.6. Direction of blood flow
3.2.6.1. Inferior vena cava
3.2.6.1.1. largest veins of the body
3.2.6.2. Superior vena cava
3.2.6.2.1. largest veins of the body
3.2.6.3. Right Atrium
3.2.6.3.1. and left atrium both contract at the same time
3.2.6.3.2. walls are thinner
3.2.6.4. Right Ventricle
3.2.6.4.1. and left ventricle simultaneously contract after the artias
3.2.6.4.2. walls are thicker
3.2.6.5. Pulmonary Valve
3.2.6.5.1. Tricuspid Valve / Right atrioventricular valve
3.2.6.5.2. formed by 3 semilunar cusps
3.2.6.5.3. prevents backflow of blood to the right ventricle when it relaxes
3.2.6.6. Pulmonary Arteries
3.2.6.6.1. left
3.2.6.6.2. right
3.2.6.7. Lungs
3.2.6.8. Pulmonary Veins
3.2.6.8.1. two pulmonary veins from each lung
3.2.6.8.2. carr oxygenated blood back to theheart
3.2.6.9. Left Atrium
3.2.6.9.1. and right atrium both contract at the same time
3.2.6.9.2. walls are thinner
3.2.6.10. Mitral Valve / Left atrioventricular valve
3.2.6.11. Left Ventricle
3.2.6.11.1. and right ventricle simultaneously contract after the artias
3.2.6.11.2. walls are thicker
3.2.6.12. Aortic valve
3.2.6.12.1. formed by 3 semilunar cusps
3.2.6.13. Aorta
3.2.6.13.1. first artery of general circulation
3.3. 'Dup'
3.3.1. softer sound
3.3.2. due to closure of aortic and pulmonary valves
3.3.3. corresponds with ventricular diastole
4. smooth muscle in the tunica media of both veins and arteries are supplied with nerves from the autonomic nervous system
4.1. they arise from the vasometer centre in the medulla oblongata
4.2. they change the diameter of the blood vessel controlling volume of blood they can contain
5. it controls BP by slowing down or speeding up heart rate and by constricting and dilating blood vessels
6. cardiovascular centre is a collection of interconnected neurones in the medulla and pons of the brain stem
6.1. the CVC receives integrates and coordinates input from Baroreceptors (pressure receptors), chemoreceptors and higher centres in the brain
7. Arteries, Veins and Capillaries
7.1. Arteries
7.1.1. Have 3 layers
7.1.1.1. Tunica intima / Inner layer; Endothelium
7.1.1.2. Tunica media / Middle layer; Smooth muscle and Elastic tissue
7.1.1.2.1. More Elastic tissue than smooth muscle
7.1.1.3. Tunica adventitia / Outer layer; Fibrous tissue
7.1.2. Have thick walls
7.1.2.1. needed to withstand the the high pressure blood flow
7.1.2.1.1. means when cut blood spurts out
7.1.3. Arteries = Away from the heart
7.1.4. Types of artery
7.1.4.1. Arterioles
7.1.4.1.1. Small arteries
7.1.4.1.2. 3 Layers
7.1.4.1.3. also know as resistance vessles
7.1.4.2. Anastomoses
7.1.4.2.1. Form a link between main arteries supplying an area eg palm of the hand, soles of the feet or brain
7.1.4.2.2. can provide collateral circulation
7.1.4.2.3. provide adequate blood supply when artery is occluded
7.1.4.3. End arteries
7.1.4.3.1. Sole source of blood supply to tissues eg central artery to the retina of the eye
7.1.4.4. when occluded tissue it supply dies as no alternative blood supply
7.1.5. Main arteries
7.1.5.1. Renal
7.1.5.1.1. kidney
7.1.5.2. Hepatic
7.1.5.2.1. liver and gall bladder
7.1.5.3. Gastric
7.1.5.3.1. Stomach
7.1.5.4. Splenic
7.1.5.4.1. spleen and pancreas
7.1.5.5. Carotid
7.1.5.5.1. neck and brain
7.1.5.6. Coronary
7.1.5.6.1. heart
7.1.5.7. Peripheral
7.1.5.7.1. limbs
7.2. Veins
7.2.1. 3 layers
7.2.1.1. Tunica intima / Inner layer; Endothelium
7.2.1.2. Tunica media / Middle layer; Smooth muscle and Elastic tissue
7.2.1.2.1. not as much as in arteries as they don't need to stretch
7.2.1.3. Tunica adventitia / Outer layer; Fibrous tissue
7.2.2. Have thin walls
7.2.2.1. withstand the low pressure blood
7.2.2.1.1. when cut slow, steady blood flow escapes
7.2.3. Veins = Carry blood towards the heart
7.2.4. also know as capacitance vessels
7.2.4.1. distensible
7.2.4.2. have capacity to hold a large proportion of the bodies blood
7.2.4.2.1. 2/3 of the body's blood is in the venous system
7.2.4.2.2. allows vascular system to absorb sudden changes in blood volume
7.2.5. Have valves
7.2.5.1. prevent backflow
7.2.5.1.1. ensuring blood flows to the heart
7.2.5.1.2. assisted by skeletal muscles surrounding the veins
7.2.5.2. formed by fold of endothelium and strengthened by connective tissue
7.2.5.3. semilunar in shape
7.2.5.3.1. concave toward the heart
7.2.5.4. abundant in veins of the limbs
7.2.5.4.1. especially lower limbs where blood has to travel a considerable distance against gravity
7.2.5.5. absent in very small and very large veins in the thorax and abdomen
7.2.6. types of vein
7.2.6.1. venules
7.2.6.1.1. small veins
7.3. Capillaries
7.3.1. Wall consists of one single layer of endothelial cells
7.3.1.1. allows water and other small molecules pass through it
7.3.1.2. blood cells and plasma proteins are usually too big to pass through the capillary wall
7.3.2. form a network that joins small arterioles to small venules
7.3.3. they are the site of exchange of substances between the blood and tissue fluid that bathes the body cell
7.3.4. Entry capillary beds are guarded by precapillary sphincters (rings of smooth muscle)
7.3.4.1. they direct blood flow
7.3.4.2. Hypoxia (low oxygen levels in the tissue) and high levels of tissue waste dilate the sphincters
7.3.4.2.1. this increases blood flow through affected beds
7.3.5. types of capilllary
7.3.5.1. Sinusoids
7.3.5.1.1. significantly wider and leakier capillaries
7.3.5.1.2. found in the liver and bone marrow
7.3.5.1.3. walls are incomplete and have larger lumens than normal
7.3.5.1.4. can come directly into contact with cells outside sinusoid walls
7.3.6. capillary refill time
7.3.6.1. when area of skin is pressed it turn white
7.3.6.1.1. because blood has been squeezed out the capillary
7.3.6.2. should take less than 2 seconds for capaillary to refill (skin to turn pink again)
7.3.6.2.1. if takes longer can suggest poor perfusions or dehydration
8. Control of blood vessel diameter
8.1. Baseline, Vasoldilation and vasoconstriction
8.1.1. vasodilation
8.1.1.1. caused by decrease nerve stimulation
8.1.1.1.1. relaxes the smooth muscle thinning the vessel wall and enlarging the lumen
8.1.1.2. increase blood flow at low pressure
8.1.2. Baseline (resting)
8.1.3. sympathetic activity / Vasoconstriction
8.1.3.1. diameter of vessel lumen and tone of the smooth muscle are determined by the degree of sympathetic activity
8.1.3.2. generally constricts vessels
8.1.3.2.1. vasoconstriction
8.1.3.2.2. this increases pressure inside the vessel
8.1.4. Relationship between sympathetic stimulation and blood vessel diameter
8.1.4.1. baseline ( Resting)
8.1.4.1.1. Sympathetic stimulation
8.1.4.1.2. smooth muscle
8.1.4.1.3. thickness of vessel wall
8.1.4.1.4. diameter of lumen
8.1.4.1.5. peripheral resistance in arterioles
8.1.4.2. Vasodilation
8.1.4.2.1. Sympathetic stimulation
8.1.4.2.2. smooth muscle
8.1.4.2.3. thickness of vessel wall
8.1.4.2.4. diameter of lumen
8.1.4.2.5. peripheral resistance in arterioles
8.1.4.3. Vasoconstriction
8.1.4.3.1. Sympathetic stimulation
8.1.4.3.2. smooth muscle
8.1.4.3.3. thickness of vessel wall
8.1.4.3.4. diameter of lumen
8.1.4.3.5. peripheral resistance in arterioles
8.2. What vessels does it effect?
8.2.1. Mainly arterioles as their walls contain more smooth muscle
8.2.1.1. responds to sympathetic stimulation
8.2.2. Large arteries such as the aorta contain more elastic tissue meaning they can expand and recoil depending on the volume of blood passing through
8.2.3. Veins also respond to nerve stimulation but only have little smooth muscle in their tunica media
8.3. Blood flow
8.3.1. resistance to flow fluids along a tube is determined by three factors
8.3.1.1. the diameter of the tube
8.3.1.2. the length of the tube
8.3.1.3. the viscosity of the fluid
8.3.2. the diameter of the resistance vessel is known as the peripheral resistnace
8.3.2.1. major factor in blood pressure regulation
8.3.2.2. Constant adjustment of blood vessel diameter helps regulate peripheral resistance and systemic blood pressure
9. Heart
9.1. Postion
9.1.1. lies in the thoracic cavity
9.1.2. in the mediastinum (space between the lungs)
9.1.3. lies slightly more on the left than the right
9.2. organs associated with the heart
9.2.1. Inferiorly
9.2.1.1. apex rests on the central tendon of the diaphram
9.2.2. superiorly
9.2.2.1. the great blood vessels
9.2.2.1.1. aorta
9.2.2.1.2. superior vena cave
9.2.2.1.3. pulmonary artery
9.2.2.1.4. pulmonary veins
9.2.3. posteriorly
9.2.3.1. oesophagus
9.2.3.2. trachea
9.2.3.3. left and right bronchus
9.2.3.4. descending aorta
9.2.3.5. inferior vena cava
9.2.3.6. thoracic vertibrae
9.2.4. laterally
9.2.4.1. the lungs
9.2.4.1.1. left lung overlaps the left side of the heart
9.2.5. anteriorly
9.2.5.1. the sternum
9.2.5.2. ribs
9.2.5.3. intercostal muscle
9.3. roughly cone shaped, hollow muscular organ
9.4. about 10cm long
9.4.1. about the size of a fist
9.5. Structure
9.5.1. the heart wall
9.5.1.1. composed of three layers of tissue
9.5.1.1.1. Pericardium
9.5.1.1.2. myocardium
9.5.1.1.3. endocardium
9.6. Blood supply to the heart
9.6.1. Arterial Supply
9.6.1.1. heart is supplied with arterial blood from fight and left coronary arteries
9.6.1.1.1. branches from the aorta
9.6.1.1.2. they recieve 5% of the blood pumped from the heart
9.6.1.1.3. traverse the heart eventually forming a vast network of capillaries
9.6.2. Venous drainage
9.6.2.1. most venous blood is collected into a number of cardiac veins
9.6.2.1.1. these join together forming coronary sinus which opens into the right atrium
9.6.2.1.2. the remainder passes directly into the heart chambers through venus channels
10. The cardiac cycle
10.1. at rest healthy heart beat for an adult is roughly 60-80 beats per min
10.2. during each hear beat the heat contracts (Systole) and then relaxes (Diastole)
10.3. stages of the cardiac cycle
10.3.1. each cycle lasts about 0.8 of a second
10.3.2. consists of 3 components
10.3.2.1. Atrial Systole
10.3.2.1.1. contraction of the artia
10.3.2.1.2. last rougly 0.1 seconds
10.3.2.2. Ventricular Systole
10.3.2.2.1. contraction of the ventricles
10.3.2.2.2. lasts roughly 0.3 seconds
10.3.2.3. Complete cardiac diastole
10.3.2.3.1. relaxation of the atria and ventricles
10.3.2.3.2. lasts roughly 0.4 seconds
10.3.3. Direction of blood flow
10.3.3.1. Atrial systole
10.3.3.1.1. Atria contract
10.3.3.1.2. AV valves open
10.3.3.1.3. Ventricles relaxed
10.3.3.1.4. Aortic/ pulmonary valves closed
10.3.3.2. Ventricular systole
10.3.3.2.1. Atria relaxed
10.3.3.2.2. AV valves closed
10.3.3.2.3. Ventricles contract
10.3.3.3. Atria and ventricles relaxed
10.3.3.4. Aortic / pulmonary valves open
10.3.3.5. Complete cardiac diastole
10.3.3.5.1. AV valves open
10.3.3.5.2. Aortic / pulmonary valves closed
11. Electrical changes in the heart
11.1. body tissues and fluid can conduct electricity well this allows electrical activity in the heart to be recorded on the skin surface using electrodes
11.1.1. this recording is called and Electrocardiagram (ECG)
11.2. ECG
11.2.1. recording of electrical activity in the heart
11.2.2. shows the spread of electrical signals produced by the pacemaker as it travels through the atria, the AV node and the ventricles
11.2.3. normal ECG tracing
11.2.3.1. Shows five waves
11.2.3.1.1. P wave
11.2.3.1.2. QRS complex
11.2.3.1.3. T wave
11.2.3.2. originates from the SA node
11.2.3.2.1. called Sinus rhythm
11.2.3.2.2. the rate of sinus rhythm is usually 60-100 b.p.m
11.2.4. ECG abnormalities
11.2.4.1. Faster heart rate is called tachycardia
11.2.4.2. slower heart rate is called is called bradycardia
12. Cardiac Output
12.1. amount of blood ejected from each ventricle every minute
12.1.1. expressed in Litres per min (L/min)
12.1.1.1. Calculated by multiplying Stroke volume by the heart rate (b.p.m)
12.1.1.1.1. Cardiac Output = Stroke volume x Heart rate
12.1.1.1.2. This can increase during exercise this is called cardiac reserve
12.2. Stroke volume
12.2.1. amount of blood expelled by each contraction of each ventricle
12.2.2. is determined by the volume of blood in the ventricles immediately before they contract
12.2.2.1. ie the ventricular end-diastolic volume (VEDV)
12.2.2.1.1. Sometimes called the preload
12.2.3. in healthy adult stroke volume is approx. 70 mL
12.2.4. Summary of affacting factors
12.2.4.1. VEDV
12.2.4.2. Venous return
12.2.4.2.1. Position of the body
12.2.4.2.2. skeletal muscle pump
12.2.4.2.3. respiratory pump
12.2.4.3. strength of myocardial contraction
12.2.4.4. blood volume
13. Blood Pressure (bp)
13.1. Blood pressure is the force / pressure that blood exerts on the walls of blood vessels
13.2. systemic arterial bp maintains the essential flow of blood into and out of organs of the body
13.3. can vary according to
13.3.1. time of day
13.3.1.1. bp falls at rest and during sleep
13.3.2. posture
13.3.3. gender
13.3.3.1. usually higher in women
13.3.4. age
13.3.4.1. increases with age
13.4. if bp gets to high it can
13.4.1. damage blood vessels
13.4.2. cause clots
13.4.3. bleed from sites of blood vessel rupture
13.4.4. result of discharge of blood from left ventricle into the already full aorta
13.5. if bp gets too low
13.5.1. blood flow through tissue bed can be inadequate
13.5.1.1. dangerous for essential organs
13.5.1.1.1. heart
13.5.1.1.2. kidneys
13.5.1.1.3. brain
13.6. Systolic
13.6.1. Arterial blood pressure
13.6.1.1. written as systolic pressure written above the diastolic pressure
13.6.1.2. measured using a sphygmomanometer
13.6.2. when the left ventricle contracts and pushes blood into the aorta
13.6.3. in adults this can be about 120 mmHg
13.7. diastolic
13.7.1. in complete cadiac diastole the pressure in the arteries is much lower
13.7.2. in adults this can be about 80 mmHg
13.8. Control of blood pressure
13.8.1. Short term regulation
13.8.1.1. on a moment to moment basis
13.8.2. long term regulation
13.8.2.1. slower longer lasting changes in blood pressure
13.8.2.1.1. Cardiovascular centre
13.8.2.1.2. affected by renin-angiotensin-aldosterone system
13.8.2.1.3. also action antidiuretic hormone
14. Pulse
14.1. normally represents the heart rate
14.2. measured in bpm
14.3. info obtained by pulse
14.3.1. rate at which the heart is beating
14.3.2. regularity of the heart beats
14.3.2.1. intervals between beats should be equal
14.3.3. volume / strenght of the beat
14.3.3.1. should be possible to compress the artery with moderate pressure
14.3.4. the tension
14.3.4.1. artery should feel soft and pliant under fingers
14.4. averaging 60-80 bpm at rest
14.5. factors affecting pulse
14.5.1. when arteries supplying peripheral tissues are blocked or narrowed
14.5.2. cardiac contraction disorders
14.5.2.1. atrial fibrillation
14.6. main pulse points
14.6.1. Temporal artery
14.6.1.1. by the eye
14.6.2. Facial artery
14.6.2.1. by the jaw
14.6.3. Common carotid artery
14.6.3.1. on the neck
14.6.4. Brachial artery
14.6.4.1. about halfway up on the inside arm
14.6.5. Radial artery
14.6.5.1. on inside of the wrist
14.6.6. Femoral artery
14.6.6.1. around the hip
14.6.7. popliteal artery
14.6.7.1. behind the knee
14.6.8. posterior artery
14.6.8.1. by the ankle
14.6.9. dorsalis pedis artery
14.6.9.1. by the toes