Lecture 6 - Cardiovascular Part II Flashcards
1
Q
2 types of circulation
A
- Systemic circulation - blood circulation around the body
- Pulmonary circulation - blood from the heart ⇒ lungs ⇒ heart
2
Q
3 types of blood vessels
A
- Arteries ⇢ arterioles (smaller arteries)
- Veins ⇢ venules (smaller veins)
- Capillaries - connect arterioles and venules, gas exchange between blood and cells/tissues
3
Q
Arteries/arterioles vs Veins/venules
A
-
Arteries/arterioes
- Carry blood AWAY from the heart
- Oxygenated (except pulmonary and umbilical arteries)
- High pressure
-
Veins/venules
- Carry blood TOWARDS the heart
- Deoxygenated (except pulmonary and umbilical veins)
- Low pressure
4
Q
Blood vessel - 3 layers
A
- Tunica externa - outermost, elastic & collagen fibres, nerves and blood vessels
- Tunica media - smooth muscle, controls blood vessel diameter
- Tunica intima - innermost, made of endothelium, protects, secretes chemicals
5
Q
Hepatic first pass
A
- Venous blood is carried by portal vein from GIT, spleen and pancreas directly to liver
6
Q
Vasoconstriction / Vasodilation
A
- Blood vessels ⇒ smooth muscle ⇒ autonomic nervous system (ANS)
- Sympathetic nervous system ⇒ vasoconstriction
- Parasympathetic - little effect
- Vasodilation ⇣ blood pressure
- Vasconstriction ⇡ blood pressure
7
Q
Heart layers
A
- Pericardium
- Myocardium
- Endocardium
8
Q
Pericardium
A
- Outer layer of the heart
- Thin, double-layered
- Fibrous pericardium - attaches to diaphragm
- Inner serous pericardium - consists of visceral and parietal layer
- Keeps heart in position
- Allows free movement during contractions
9
Q
Myocardium
A
- Middle layer
- Cardiac muscle - 95% of heart
- Striated and involuntary
- Pumps blood out of the heart
- Autorhythmic (can generate its own rhythm of contraction)
10
Q
Endocardium
A
- Innermost layer
- Thin layer of endothelium over thin layer of connective tissue
- Smooth lining for the heart chambers, covers heart valves
11
Q
Cardiac artery
A
delivers oxygenated blood to the mycardium
12
Q
4 chambers of the heart
A
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
13
Q
Right Atrium
A
- Receives deoxygenated blood from superior and inferior vena cava
- Pumps blood into right ventricle through tricuspid valve
14
Q
Right Ventricle
A
- Receives deoxygenated blood from right atrium
- Pumps blood to lungs through the pulmonary valve into the pulmonary trunk which divides into left and right pulmonary arteries
15
Q
Left Atrium
A
- Receives oxygenated blood from lungs via pulmonary vein
- Pumps blood to the left ventricle through the mitral / bicuspid valve
16
Q
Left Ventricle
A
- Receives oxygenated blood from the left atrium
- Pumps blood through the aortic valve into the ascending aorta. Some of the blood flows into the coronary arteries which carry blood to the heart wall
17
Q
Blood flow in heart
A
- Blood enters right atrium from the superior and inferior vena cava
- Goes through the tricuspid valve into the right ventricle
- Passes through the pulmonary valve into the pulmonary artery into the lungs
- Blood (now oxygenated) returns to left atrium via the pulmonary vein
- Passes through the mitral valve into the left ventricle
- Pumped through the aortic valve into the aorta
18
Q
Heart contraction - sympathetic and parasympathetic nervous systerms
A
-
Sympathetic Nervous System
- ⇑ Increases rate and strength of contraction
- Vasoconstriction
-
Parasympathetic Nervous System
- ⇓ Decreases rate and strength of contraction (via vagus nerve)
- Little influence on blood vessels
19
Q
Conduction system of the heart - components
A
- Sinoatrial node (SA node) - pacemaker
- Atrioventricular node (AV node) - relay station
- Atrioventricular bundle (bundle of His) - conduct from atria to ventricles
- Right and left bundle branches
- Purkinje fibres - ventricular contraction
20
Q
What is the primary fuel for the heart?
A
Fatty acids (50-70%), glucose (30%)
During exercise - lactic acid to produce ATP
21
Q
ECG
A
- P wave - atrial depolarisation (SA node)
- QRS wave - rapid ventricular depolarisation (sharp curve)
- T wave - ventricular repolarisation (resting)
Enlarged Q wave may suggest heart attack
22
Q
Pulse Rate
A
- Blood pressure wave original from the heart
- Varies depending on life stage
- Newborn 130
- 3 years 100
- 12 years 85
- Adult 70-90
23
Q
Cardiac output
A
Volume of blood being pumped out by the heart per minute
Stroke volume = volume ejected per beat from both ventricles
Cardiac output = stroke volume x heart rate (average 5 L / min
24
Q
Systole
A
The force that drives blood out of the heart (contraction)
25
Diastole
Period of **relaxation** when the heart fills with blood
26
Tachycardia
Resting heart rate over 100 bpm
27
Bradycardia
Resting heart rate under 60 bpm
28
What is blood pressure?
Pressure exerted by circulating blood on the blood vessel walls
Normal range 90/60 - 140/90 mmHg
Vasoconstriction ⇑ bp
Vasodilation ⇓ bp
29
Cholesterol - functions
* Cell membrane integrity (vital in brain)
* Vitamin D and calcium metabolism
* Sex hormones (e.g. oestrogen, testosterone)
Acquired from liver cells and diet
Hydrophobic - must be transported by lipoproteins
30
Lipoproteins
* Low density lipoproteins (LDL)
* High density lipoproteins (HDL)
NHS guidelines - total cholesterol levels 5 mmol/L or less for healthy adults and 4 mmol/L or less for at risk
31
Low density lipoproteins (**LDL**)
* Carry 75% total cholesterol in body - from liver to cells
* In excess, can be deposited in arteries
32
HDL (high density lipoproteins)
* **Remove excess** cholesterol from body cells and blood, transport to **liver**
* Prevent accumulation of cholesterol in blood
33
Blood - homeostasis - body systems
* **Skin** - repair, temperature
* **Skeletal** - bone remodelling, RBC production
* **Muscular** - transports heat and lactic acid
* **Endocrine** - delivers hormones to target tissues
* **Lymphatic/immune** - distribute immune cells
* **Digestive** - carry nutrients to liver, hormones for digestion
* **Urinary** - 20% of cardiac output ⇢ liver for filtering
* **Reproductive** - distribute hormones
34
Hypercholesterolaemia
Elevated blood cholesterol
Allopathic treatment - statins
35
Hypercholesterolaemia - causes
* Familial (chromosomal defect)
* Age
* Hypertension
* Diabetes
* Obesity
* Smoking
* Sedendary lifestyle
* Diet (high trans fats, salt, refined sugars)
* Exessive alcohol
36
Arterioscelerosis
Thickening and loss of elasticity of arterial walls
37
Atherosclerosis
* A type of arteriosclerosis
* Formation of atherosclerotic plaques in arterial walls - disrupt blood flow
* Affects medium and large arteries (coronary, carotid, cerebral, aorta)
* Leading cause of death in US and most developed countries
38
Cardiac Arrest
* Not a heart attack
* Occurs when heart develops an arrhythmia causing it to stop
* 70% due to coronary heart disease
* Other causes - cardiomyopathy, trauma, medication overdose, haemorrhage
39
Endocarditis
Inflammation of the endocardium and valves
Bacterial infection which spread from a dental infection
Symptoms
* Fever, fatigue, muscle & joint pain, loss of appetite (flu-like)
* Dyspnoea and persistent cough
* Osler's nodes (tender red pots under skin of fingers)
40
Pericarditis
Acute inflammation of pericardium
Normally viral infection, can be systematic inflammation (RA)
Signs
* chest pain radiating to back, relieved by sitting up
* dyspnoea when reclining
* Low-grade fever, weakness, fatigue, nauseous, dry cough
* Pericardial friction rub
41
Shock
Reduction in circulating blood volume, blood pressure and cardiac output
Resulting in hypoxia of tissues
42
3 types of shock
1. **Hypovolaemic** - blood volume reduced by 15-25%, hemorrhage, severe burn, vomiting, diarrhoea
2. **Cardiac** - myocardium can't maintain cardiac output
3. **Septic** - infection causes immune and inflammatory response causing vasodilation and pooling of blood
43
Neurogenic Shock
* Loss of sympathetic control on blood vessels
* Increased parasympathetic stimulation of heart
* Dilation of blood vessels and bradycardia
* Casuses reduced cardiac output, blood pooling and fainting
* E.g. spinal injury
44
Anaphylactic shock
* Severe allergic response
* Vasodilation
* Bronchoconstriction
* Reduced cardiac output
* Tissue hypoxia
45
Signs and symptoms of shock
* Hypoxia - cold, clammy, cyanosis, faint, weak
* Confusion, anxiety
* Tachycardia
* Weak pulse
* Rapid breathing
* Hypotension
