Physiology

Question 1

Where are the respiratory centres in the brainstem?

Answer 1

Respiratory rhythm is generated in the medulla

Respiration is modifies by inputs from the pons

Question 2

The respiratory centres in the brainstem are influenced by stimuli from where?

Answer 2

• Central chemoreceptors
• Peripheral chemoreceptors
• Higher brain centres e.g. cortex, limbic system, hypothalamus
• Stretch receptors in wall of bronchi and bronchioles
• Juxtapulmonary receptors
• Joint receptors
• baroreceptors

Question 3

What is the name of the reflex which protects against hyperinflation of the lungs?

Answer 3

inflation Hering-Bruer reflex

Question 4

What stimulates the juxtapulmonary receptors and what effect does this have on breathing?

Answer 4

Juxtapulmonary receptors are stimulated by pulmonary capillary congestion, pulmonary oedema, and pulmonary emboli
- stimulates rapid shallow breathing

Question 5

What is the role of baroreceptors in respiration?

Answer 5

Baroreceptors stimulate increased ventilatory rate in response to decreased BP

Question 6

What factors stimulate the respiratory centres to increase awareness of breathing discomfort (shortness of breath)

Answer 6

Hypoxia
Acidosis
Hypercapnia
Central arousal e.g. anxiety
Increased body temperature
Pain
Joint movements during exercise
Drugs e.g. amphetamines

Question 7

Name 2 peripheral chemoreceptors.

What is the role of peripheral chemoreceptors?

Answer 7

Aortic bodies and carotid bodies

Sense tension of O2, CO2, and H+ in the blood

Question 8

Where are the central chemoreceptors located?

Answer 8

Near the surface of the medulla of the brainstem

Question 9

What is the role of the central chemoreceptors?

Answer 9

Respond to H+ concentration of the CSF

Question 10

What are the two types of calcium channel blockers?

Answer 10

Dihydropyridines (e.g. amlodipine) - don’t affect contractility or rate of heart
L-type (e.g. verapamil) - do affect contractility and rate

Question 11

What is the treatment for acute heart failure?

Answer 11

IV furosemide - relieves pulmonary oedema

Nitrates infusion - venodilatation in the lungs to relieve oedema and also systemic ventilation to relieve preload

Question 12

What are the common causes of AF?

Answer 12

IHD
Hypertension
Hyperthyroid
pneumonia
alcohol
valvular heart disease

Question 13

How does hyperthyroidism cause tachycardia and AF?

Answer 13

Thyroid hormones potentiate the effect of catecholamines on the heart

Question 14

What ABG results will you get in a panic attack?

Answer 14

respiratory alkalosis, with normal O2 (and normal HCO3)

Question 15

What might you hear when auscultating the chest in a PE?

Answer 15

Pleural rub

Question 16

What are the types of cysts that occur in the ovary?

Answer 16

Follicular
Luteal
Endometriotic ("chocolate")
Epithelial
Mesothelial

Question 17

What are functional cysts?

Answer 17

Related to cyclical development and atresia of ovarian follicles.
Follicular cysts are the most common functional cyst (small ones are found in most premenopausal ovaries)
Luteal cysts are less common

Question 18

What type of cyst is found in PCOS?

Answer 18

follicular cysts - the follicle grows but does not rupture and so becomes a cyst

Question 19

What is endometriosis?

Answer 19

Endometrial glands and stroma outside the uterine body

Question 20

What would you expect the FEV1/FVC ratio to be in pulmonary fibrosis and why?

Answer 20

normal/sightly increased - the fibrosis increases the elastic recoil and can hold the airways open so FEV1 is high.

Question 21

What are the features of endometriosis?

Answer 21

May cause pelvic inflammation, infertility (due to adhesions), and pain.
Commonest site is the pouch of Douglas, but also found on ovary, peritoneal surfaces, uterus, cervix, bladder, bowel

Question 22

Patient with a right lower lobe lung cancer, has shortness of breath at night and when he is on his own. On auscultation his heart sounds are normal and there are some crackles in the right lower lobe? What is the best management?

Answer 22

Lorazepam - reduces anxiety which is causing the breathlessness. The breath sounds are unilateral which means it is unlikely to be pulmonary oedema, and likely to be due to the tumour.