Heart and Lungs Week 4

Question 1

Understand the normal maintenance and control of blood pressure ?

Answer 1

Blood pressure is measured in millimetres of mercury (mmHg) and is given as 2 figures:

systolic pressure – the pressure when your heart pushes blood out

diastolic pressure – the pressure when your heart rests between beats

Regulation of blood pressure is an example of negative feedback.

Blood vessels have sensors called baroreceptors that detect if blood pressure is too high or too low and send a signal to the hypothalamus.

The hypothalamus then sends a message to the heart, blood vessels, and kidneys, which act as effectors in blood pressure regulation. If blood pressure is too high, the heart rate decreases as the blood vessels increase in diameter ( vasodilation ), while the kidneys retain less water.

These changes would cause the blood pressure to return to its normal range. The process reverses when blood pressure decreases, causing blood vessels to constrict and the kidney to increase water retention.

Baroreceptors are sensory neurons that monitor arterial blood pressure. Major baroreceptors are located in the carotid sinus (an enlarged area of the carotid artery just above its separation from the aorta), the aortic arch, and the right atrium.

Question 2

How does Antidiuretic hormone (ADH) effect blood pressure ?

Answer 2

Antidiuretic hormone (ADH), a hormone produced by the hypothalamus and released by the posterior pituitary, raises blood pressure by stimulating the kidneys to retain H 2O (raising blood pressure by increasing blood volume).

Question 3

How does Atrial natriuretic peptide (ANP) effect blood pressure ?

Answer 3

Atrial natriuretic peptide (ANP), a hormone secreted by the atria of the heart, lowers blood pressure by causing vasodilation and by stimulating the kidneys to excrete more water and Na +(lowering blood pressure by reducing blood volume).

Question 4

What is the effect of alcohol on blood pressure ?

Answer 4

increases blood pressure

Question 5

What is the effect of nicotine on blood pressure ?

Answer 5

Nicotine in tobacco raises blood pressure by stimulating sympathetic neurons to increase vasoconstriction and by stimulating the adrenal medulla to increase secretion of epinephrine and norepinephrine.

Question 6

What effect does epinephrine (aka adrenaline ) have on blood pressure ?

Answer 6

Epinephrine and norepinephrine, hormones secreted by the adrenal medulla, raise blood pressure by increasing heart rate and the contractility of the heart muscles and by causing vasoconstriction of arteries and veins. These hormones are secreted as part of the fight‐or‐flight response.

Question 7

Know which arteries most useful for determining pulse and arterial perfusion ?

Answer 7

• Pulse pressure is the difference between systolic and diastolic blood pressures.

Pulse Pressure = Systolic Blood Pressure – Diastolic Blood Pressure

The systolic blood pressure is defined as the maximum pressure experienced in the aorta when the heart contracts and ejects blood into the aorta from the left ventricle (approximately 120 mmHg). The diastolic blood pressure is the minimum pressure experienced in the aorta when the heart is relaxing before ejecting blood into the aorta from the left ventricle (approximately 80 mmHg). Normal pulse pressure is, therefore, approximately 40 mmHg.

The radial artery is most commonly used to check the pulse.

Question 8

Describe the functional histology of arteries and arterioles ?

Answer 8

There are 3 main types of arteries

Question 9

Describe the 3 main types of arteries ?

Answer 9

3 main types of arteries: elastic, muscular and arterioles

• Elastic arteries - these arteries receive blood directly from the heart (aorta and pulmonary artery). These need to be elastic so when the heart contracts and ejects blood into these arteries, the walls need to stretch to accommodate the blood surge. Between heart contractions the elastic walls recoil to maintain blood pressure even when the ventricles are relaxed.
• Muscular arteries - distribute blood to different parts of the body. They include femoral and coronary arteries. The walls of these arteries have lots of smooth muscle which means they are able to contract or relax to chnage the
• Arterioles

Question 10

Describe the 3 main types of arteries ?

Answer 10

3 main types of arteries: elastic, muscular and arterioles

• Elastic arteries - these arteries receive blood directly from the heart (aorta and pulmonary artery). These need to be elastic so when the heart contracts and ejects blood into these arteries, the walls need to stretch to accommodate the blood surge. Between heart contractions the elastic walls recoil to maintain blood pressure even when the ventricles are relaxed.
• Muscular arteries - distribute blood to different parts of the body. They include femoral and coronary arteries. The walls of these arteries have lots of smooth muscle which means they are able to contract or relax to change the amount of blood delivered.
• Arterioles - are small arteries that deliver blood to capillaries.

Question 11

Describe the histology of arterioles ?

Answer 11

• lumen is very small
• The tunica intima is very thin, and mostly consists of a single layer of squamous epithelium.The tunica media consists almost entirely of a single layer up to six layers of smooth muscle cells, and there is no EEL. The Tunica adventitia is about the same size as the tunica media layer, merges in with surrounding tissue.

Question 12

Describe the histology of muscular arteries ?

Answer 12

• compared to elastic arteries have much less elastic layer and more smooth muscle.

Question 13

Review the location and function of alpha and beta adrenoreceptors in the CVS ?

Answer 13

Beta-1 receptors, Beta-2, Alpha-1, and Alpha-2 receptors, are adrenergic receptors primarily responsible for signaling in the sympathetic nervous system.

Beta-agonists bind to the beta receptors on various tissues throughout the body.

Beta-1 receptors are predominantly found in three locations: the heart, the kidney, and the fat cells.

Question 14

How do Beta - 1 adrenergic receptors work ?

Answer 14

The beta-1 adrenergic receptor is a G-protein-coupled receptor communicating through the Gs alpha subunit. By signaling Gs, a cAMP-dependent pathway is initiated through adenylyl cyclase, and this results in potentiation of the receptor’s function.

Question 15

Where are alpha and beta adrenoreceptors found ?

Answer 15

Both alpha and beta receptors are located on the postsynaptic membrane at the sympathetic junctions.

Both alpha and beta receptors are stimulated by epinephrine and norepinephrine.

Question 16

Difference between alpha and beta adrenoreceptors ?

Answer 16

Alpha Receptors: Alpha receptors are the cell receptors that control physiological processes like vasoconstriction, intestinal relaxation, pupil dilation upon interaction with epinephrine and norepinephrine.

Beta Receptors: Beta receptors are a group of receptors that control vasodilation, relaxation of the bronchial and uterine smooth muscles, and increased heart rate.

Effect:

Alpha Receptors: Alpha receptors stimulate effector cells.

Beta Receptors: Beta receptors relax effector cells.

Types:

Alpha Receptors: The two types of alpha receptors are alpha 1 and alpha 2.

Beta Receptors: The three types of beta receptors are beta 1, beta 2, and beta 3.

Occurrence:

Alpha Receptors: The two types of alpha receptors are alpha 1 and alpha 2.

Beta Receptors: The three types of beta receptors are beta 1, beta 2, and beta 3.

Muscle stimulation:

Alpha Receptors: Alpha receptors stimulate smooth muscles.

Beta Receptors: Beta receptors stimulate both cardiac and smooth muscles.

Examples:

Alpha Receptors: The stimulation of alpha receptors in the heart constricts blood vessels.

Beta Receptors: The stimulation of beta receptors in the heart increases the heart rate and the strength of contraction.

Question 17

When does the heart start beating ?

Answer 17

23 days after fertilization

Question 18

How much blood on average does the heart pump out in a minute ?

Answer 18

5.250 L of blood per min

Question 19

Describe the layers of the heart ?

Answer 19

Question 20

Describe sarcomeres in cardiomyocytes ?

Answer 20

Question 21

Describe the action potential of the SA ?

Answer 21

Question 22

At what point does the esophagus, aorta and inferior vena cava go through the diaphragm ?

Answer 22

I ate (8) 10 Oreos at 12

Aortic - T8

Oesophagus - T10

Aortic - T12

Question 23

Describe the internal anatomy of an artery or vein ?

Answer 23

Question 24

What is the difference between elastic artery. muscular artery and arterioles ?

Answer 24

Question 25

What are the 3 types of capillaries ?

Answer 25

Question 26

Describe the structures found in the capillaries ?

Answer 26

- Precapillary sphincters: A precapillary sphincter is a band of contractile mural cells either classified as smooth muscle or pericytes that adjusts blood flow into capillaries. - Vascular shunt: A blood vessel that links an artery directly to a vein, allowing the blood to bypass the capillaries in certain areas. This useful at times when tissues don't need blood. This is very clever the body can send the blood to where it is needed the most.

Question 27

Describe how the veins serve as a volume reservoir ?

Answer 27

Question 28

Describe how the veins serve as a volume reservoir ?

Answer 28

Question 29

Describe how the arteries act as a pressure reservoir ?

Answer 29

Arteries are low resistance vessels that serve as pressure reservoirs to maintain blood flow during diastole. All arteries have muscular walls. In response to pressure, to paracrines, and to nervous activity, the smooth muscle of the artery can either constrict or relax and thereby change the diameter of the vessel.

Question 30

Does blood pressure vary ?

Answer 30

Blood pressure is different in blood vessels and varies from minute to minute dependent on factors such as stress.

Question 31

Describe a blood pressure reading ?

Answer 31

Question 32

How do you work out the mean arterial pressure (MAP) ?

Answer 32

Question 33

What aids venous return to the blood ?

Answer 33

Question 34

What is the difference between Cardiac Output (CO), Stroke Volume and Heart Rate ?

Answer 34

Question 35

What are the 3 factors stroke volume is determined by ?

Answer 35

Preload: Preload (End Diastolic Volume)>>> the higher the volume, the higher the stroke [Frank-Starling law of the heart] Factors affecting preload: - blood volume - venous return Afterload: is the pressure that the ventricles must overcome to eject blood. It is essentially the back pressure that arterial blood exerts on the aortic and pulmonary valves—about 80 mm Hg in the aorta and 10 mm Hg in the pulmonary trunk

Question 36

What is catecholamine ?

Answer 36

- A type of neurohormone (a chemical that is made by nerve cells and used to send signals to other cells). Catecholamines are important in stress responses. High levels cause high blood pressure which can lead to headaches, sweating, pounding of the heart, pain in the chest, and anxiety.

Question 37

What is catecholamine ?

Answer 37

- A type of neurohormone (a chemical that is made by nerve cells and used to send signals to other cells). Catecholamines are important in stress responses. High levels cause high blood pressure which can lead to headaches, sweating, pounding of the heart, pain in the chest, and anxiety.

Question 38

What is hematocrit ?

Answer 38

Question 39

What is arterial occlusion ?

Answer 39

Acute arterial occlusion is a sudden blockage or closing of one of your peripheral arteries that interrupts blood flow. Healthcare providers also call this condition acute limb ischemia. “Ischemia” means part of your body isn't receiving enough oxygen-rich blood. Occlusion can increase blood pressure dramatically. A 20% occlusion of a healthy artery can increase blood pressure from 120mmHg to 293mmHg.

Question 40

What happens to blood pressure when you have arteriosclerosis ?

Answer 40

Atherosclerosis is the buildup of fats, cholesterol and other substances in and on the artery walls. This buildup is called plaque. The plaque can cause arteries to narrow, blocking blood flow. The plaque can also burst, leading to a blood clot.

Answer 41

Higher blood pressure, higher chance of bad things happening

Question 42

How do we generate and maintain our own blood pressure ?

Answer 42

- Dependent on blood flow, change in pressure and resistance.

Question 43

Statistics about heart ?

Answer 43

Question 44

What happens during diastole and systole ?

Answer 44

Diastole: Blood flows from atria to ventricles Systole: Blood is ejected from the ventricles

Question 45

What is the equation to work out blood flow ?

Answer 45

Question 46

What happens to resistance of blood during exercise ?

Answer 46

- In exercise the body changes the resistance of blood vessels to divert the blood to where it is needed. If resistance falls blood flow increases If resistance rises blood flow decreases We need to remember when resistance is falling so is pressure, we need to increase our cardiac output somehow ? This is done easily by increasing heart rate. And is the reason why our heart rate increases during exercise. CO = HR x SV An increase in cardiac output increases the pressure we can generate and compensates the fall in resistance which is increasing our blood flow.

Question 47

What happens to blood flow rate when the diameter of a vessel is increased ?

Answer 47

Doubling the diameter (lumen ) of a vessel increases the blood flow rate by 4. This is shown by Poiseuille's Law

Question 48

How do we control local control of blood flow ?

Answer 48

Local control of blood flow is generally controlled though metabolic products of the tissues affecting the vascular bed. Vasodilation causes: - So vasodilation can be induced by cytokines when blood vessels are damaged. Nitric oxide is a good example of this. - High CO2 levels can lead to vasodilation - This makes sense because if you damage to tissue or vessels, then you need to get inflammatory products circulating the body to that tissue. So you want to increase blood flow to that tissue bed. -Similarly CO2 is a waste product that is harmful to the body. If you have high concentrations of it in a certain area of the body, increasing vasodilation increases blood flow away. Vasoconstriction causes: - Low oxygen: If you have low oxygen levels in the blood you may want to vasoconstrict to divert blood away from areas that is may not be needed to those who do need it eg. heart, brain and major organs - Acidity - Potassium and bicarbonate

Question 49

What is the central control of blood pressure ?

Answer 49

The central control of blood pressure can be split into two categories: 1. Autonomic nervous system - which is driven by the sympathetic nervous system and has a very fast acting effect. 2. Endocrine system - which has various different hormonal pathways - the endocrine system has a longer term effect than the autonomic nervous system.

Question 50

What doe the sympathetic fibers do to the vessels ?

Answer 50

Every single blood vessel apart from the capillaries is innervated by the sympathetic nerve.

Question 51

Describe how sympathetic activation affects blood flow and blood pressure ?

Answer 51

Vasconstriction: - Increases peripheral resistance which increases blood pressure - increases venous pressure = increases blood flow back to the heart = increases SV Increased heart rate: - increases cardiac output = increases blood pressure Increased inotropy: - increases stroke volume = increased cardiac output = increased blood pressure Increased adrenaline / noradrenaline secretion from adrenal glands: - Activate alpha - and beta-adrenergic receptors - Vasoconstriction, increased heart rate, increased inotropy Pressure = Cardiac output x Resistance Cardiac output = HR x SV

Question 52

What causes sympathetic activation to be stimulated ?

Answer 52

Possible causes: exercise, emotional stress, changes in intravascular pressure Sympathetic reaction is governed by changes in blood pressure itself. Change in blood pressure can cause sympathetic activation or deactivation. Baroreceptors detect a change in pressure Arterial baroreceptors (pressure receptors) are found in: - Aortic arch - Internal carotid arteries As the pressure increases the vessels stretch. Baroreceptors detect this stretch. Vascular stretch causes an increase in efferent impulses which activate the sympathetic nervous system. This works in a negative feedback loop.

Question 53

Describe blood pressure and negative feedback loop?

Answer 53

The process is called Vasomotor tone. Decreased blood pressure Decreased firing from baroreceptors Vasomotor centre in the medulla Increased sympathetic activation Increased blood pressure Detected by baroreceptors when they stretch. Which increases firing from baroreceptors Send efferent signals to the vasomotor centre in the medulla This decreases sympathetic activation Which decreases blood pressure

Question 54

Why are baroreceptors important ?

Answer 54

Baroreceptors minimise variations in our BP regardless of cause. This is why we do not feel dizzy when we get out of bed in the morning and we do not get severe headaches and blurred vision when we become excited.

Question 55

How does hypoxia cause high blood pressure ?

Answer 55

Low levels of oxygen, can cause vasoconstriction to divert blood to where it is most needed.

Question 56

What layer of the embryo contributes to the arteries and cardiac outflow?

Answer 56

The mesoderm

Question 57

Which layer of the embryo forms the blood and heart?

Answer 57

mesoderm

Question 58

What does the truncus arteriosis or bulbus cordis do and where is it?

Answer 58

It is at the top of the fused heart tubes and forms the aortic arch and most of the right ventricle

Question 59

Describe the steps for the embryology of the heart ?

Answer 59

Day 19: precursor cells start to become endocardial tubes. Day 21: during lateral and cephocaudal folding the two heart tubes fuse into one single primitive tube. Day 22: the heart begins to beat Day 23- 28: looping of the heart Day 28- 46 (approx): septum divide heart into different chambers

Question 60

How does blood return to the heart from the yolk sac and developing foregut ?

Answer 60

Vitelline veins

Question 61

What is septum premium ?

Answer 61

Grows from the roof of the atrium towards the endocardial cushions

Question 62

Where does the right and left horns of sinus venous receive blood from ?

Answer 62

The common cardinal vitelline veins and umbilical veins

Question 63

What occurs as a result of aortic or pulmonary stenosis ?

Answer 63

Left and right wall ( respectively ) become thickened ( hypertrophied), stenosis ( narrowing) of the valves restricts flow; these together result in a heart murmur

Question 64

Where do vitelline arteries bring blood to ?

Answer 64

The yolk sac and future gut

Question 65

Label the primitive heart tube

Answer 65

Truncus arteriosus: aorta, pulmonary trunk Bulbus cordis: right ventricle ( trabeculated part, proximal), ventricle outflow tracts Primitive ventricle: left ventricle ( trabeculated part) Primitive atrium: right and left atrium (anterior parts) Sinus Venosus: right atrium ( smooth parts )

Question 66

Which cells form the definitive mitral and tricuspid valves ?

Answer 66

Mesenchymal cells

Question 67

How does oxygenated blood from the placenta return to the embryos heart ?

Answer 67

Via the umbilical vein

Question 68

What do the vitelline arteries represent in an adult ?

Answer 68

Celiac, superior and inferior mesenteric arteries

Question 69

Describe the order of blood flow in the newly formed heart ( pre looping )

Answer 69

From bottom to top: 1. Sinus venosus 2. Primitive atria 3. Primitive ventricle 4. Bulbus cordis 5. Truncus arteriosus 6. Aortic sac 7. Dorsal aorta

Question 70

Describe the inflow tract of the early embryo ? ( pre looping )

Answer 70

Sinus venous receives paired umbilical, vitelline and common cardinal veins

Question 71

Which germ layer are the lungs formed from ?

Answer 71

Endoderm layer. The lungs originate from the ventral aspect of the foregut. This is known as the respiratory diverticulum which later becomes the lung bud

Question 72

Which week do we get the separation of the trachea and oesophagus (tracheal oesophageal ridge )

Answer 72

The foregut has differentiated into the trachea and oesophagus by week 4

Question 73

What is the tracheooesphageal fistula ?

Answer 73

Separation of the trachea and oesophagus

Question 74

Where do the supporting structures of the lung develop from ?

Answer 74

Mesenchyme layer of the mesoderm

Question 75

Where are the actual lungs derived from and where is the pleura derived from ?

Answer 75

Actual lungs: ectoderm Pleura: splanchnic mesoderm

Question 76

Describe the development of the lungs ?

Answer 76

28 days we can see the bronchial buds 35 days we can see the left and right main bronchus 42 days the branching levels will be more complex and proliferate into a, b and c

Question 77

What are the 5 stages of the lung maturation period?

Answer 77

Embryonic stage ( 3-6 week) Pseudo glandular stage ( 5-17 week ) Canalicular stage (16-25 week ) Terminal sac / saccular stage ( 24 weeks until birth) Alveolar stage ( 36 weeks - 8years )

Question 78

Describe the embryonic stage of lung development ( 3-6 weeks) ?

Answer 78

- respiratory diverticulum appears on the foregut - caudal end of trachea bifurcate into the left and right bronchial buds which continue to grow into the adjacent layer of splanchnic mesoderm derived pleural mesenchyme - at the end of the 5th week- the primary bronchial buds divide asymmetrically to form the secondary bronchial buds. 2 on the left and 3 on the right , which will give rise to future lobes

Question 79

The left renal artery leaves the aorta at what point ? The testicular and ovarian arteries leave the aorta at what point ?

Answer 79

1. L1 2. L2

Question 80

What is the bifurcation point of the abdominal aorta ?

Answer 80

L4: bifurcation of the abdominal aorta

Question 81

Describe the arteries stemming off the brachiocephalic trunk and right subclavian artery ?

Answer 81

Question 82

Where does the right internal and external carotid artery lie ?

Answer 82

Question 83

Common carotid arteries on a cadaver ?

Answer 83

Question 84

Facial artery and superficial temporal artery ?

Answer 84

Question 85

Branches of left common carotid artery and left subclavian artery ?

Answer 85

Question 86

What are the branches of the descending aorta ?

Answer 86

Question 87

What are the branches of the inferior vena cava ?

Answer 87

Question 88

What are the branches of the superior vena cava ?

Answer 88

Question 89

Where does the descending thoracic aorta run from ?

Answer 89

T4 to T12

Question 90

Where does the abdominal aorta run from ?

Answer 90

Starts at T12 and bifurcates at L4 into the right and left common iliac arteries.

Question 91

How does the inferior vena cava arise ?

Answer 91

The left and right common iliac veins arising as the anastomosis (joining) of the external and  internal iliac veins on either side. The inferior vena cava (formed by the anastomosis of the right and left common iliac veins the level of L5 – runs on right side of vertebral column – is partially embedded in the liver before passing through the caval opening of the diaphragm at T8, and entering the right atrium) Renal veins - L1 Gonadal veins - L2

Question 92

Where does deoxygenated blood from the superior vena cava come from ?

Answer 92

Question 93

Where does blood draining into the azygous vein come from ?

Answer 93

Question 94

The superior vena cava is formed by the union of the brachiocephalic veins

Answer 94

Question 95

Veins

Answer 95

Question 96

Right internal jugular and left internal jugular

Answer 96

Question 97

External and internal iliac arteries ?

Answer 97

Question 98

External and internal iliac veins ?

Answer 98

Question 99

IMPORTANT

Answer 99

Question 100

The inferior vena cava runs alongside the side of the abdominal aorta

Answer 100

- Below the kidneys we have the inferior mesenteric artery.

Question 101

Iliac arteries and veins

Answer 101

Question 102

What does the external iliac artery supply ? What does the internal iliac artery supply ?

Answer 102

Question 103

The external iliac artery changes name to the femoral artery

Answer 103

Question 104

The femoral artery, femoral vein and femoral nerve run alongside each other.

Answer 104

Question 105

What is the popliteal fossa ?

Answer 105

The Popliteal Fossa is a diamond-shaped space behind the knee joint. It is formed between the muscles in the posterior compartments of the thigh and leg. This anatomical landmark is the major route by which structures pass between the thigh and leg. The popliteal artery passes through the popliteal fossa and ends at the lower border of the popliteus muscle, where it branches into its two terminal branches; the anterior and posterior tibial arteries.

Question 106

Posterior and anterior tibial artery ?

Answer 106

Question 107

What are the branches of the coeiliac / celiac trunk ?

Answer 107

Celiac trunk arises from the aorta at T12. It’s branches are the splenic artery , hepatic artery and the left gastric artery

Question 108

Where does the left testicular vein drain into ?

Answer 108

Left and right testes are drained by the left and right testicular/gonadal vein respectively. The right testicular vein drains directly into the inferior vena cava, while the left testicular vein drains into the left renal vein which then drains into the inferior vena cava.