Anatomy and Physiology

Question 1

What are the functions of the nasal cavity, relating to its structure?

Answer 1

• Many blood vessels to warm air. Explains large blood loss during epistaxis (nosebleed).
• Hairs and mucous filter air.
• Olfaction (sense of smell): chemoreceptors detect odour molecules, signals carried to brain.

Question 2

What are the functions of the pharynx, relating to its structure?

Answer 2

• Passageway of air to the lungs and swallowed food and drink into oesophagus.
• Swallowing: soft palate and uvula are pushed upwards, preventing entry of food into respiratory tract.
• Pharyngeal smooth muscles keep pharynx permanently open.
• Resonating chamber for speech.

Question 3

What are the functions of the larynx, relating to its structure?

Answer 3

• Epiglottis rises upwards behind tongue, preventing inhalation of foreign objects.
• Production of sound: air flowing upwards vibrates vocal cords.

Question 4

Describe the process of inhalation.

Answer 4

External intercostal muscles and diaphragm contract, increased thorax volume lowers pressure inside thorax, air from atmosphere forced into lungs as pressure is lower in lungs than atmosphere.

Question 5

Describe the process of exhalation.

Answer 5

External intercostal muscles and diaphragm contract, decreased thorax volume increases pressure inside thorax, pressure is greater inside the thorax than in the atmosphere, air forced out of thorax.

Question 6

What is surfactant?

Answer 6

Surfactant is a phospholipid layer which means it prevents collapse as phospholipids line up facing aqueous outside.

Question 7

Which cells secrete surfactant?

Answer 7

Septal cells in the alveolar walls.

Question 8

List some possible causes of an increased respiratory rate.

Answer 8

Fever, dehydration, asthma, COPD, hyperventilation, infections, respiratory acidosis, drug overdoses, heart conditions, lung cancer, pulmonary embolism.

Question 9

What is bradypnoea?

Answer 9

Slow breathing

Question 10

What is the normal pH of blood?

Answer 10

7.35-7.45

Question 11

How does a pulse oximeter work?

Answer 11

It emits red and near-infrared light from one side of the probe, and detects it on the other side, after the light has passed through the tissues of the body. The amount of each type of light absorbed by both oxygenated and deoxygenated haemoglobin is measured and is used to calculate the oxygen saturation of the arterial blood.

Question 12

What are the main functions of the kidney?
(tip: there is a useful acronym)

Answer 12

A – Maintaining ACID-BASE BALANCE.
W – Maintaining WATER BALANCE.
E – Maintaining ELECTROLYTE BALANCE.
T – TOXIN removal.
B – Control of BLOOD PRESSURE.
E – Produces ERYTHROPOIETIN.
D – Metabolism of vitamin D.

Question 13

What percentage of cardiac output is taken by the kidneys and why is this important?

Answer 13

20-25% - ensures that the kidneys can filter blood very quickly and effectively to maintain homeostasis.

Question 14

Describe how the juxtaglomerular apparatus responds to low blood volume and low blood pressure?

Answer 14

• Juxtaglomerular cells release renin.
• Renin turns angiotensinogen into Angiotensin I.
• Angiotensin-Converting-Enzymes (ACE) in lungs turn Angiotensin I to Angiotensin II.
  -Angiotensin II causes vasoconstriction, adrenal cortex to release aldosterone (decreases urination by increasing sodium and water reabsorption), ADH released, stimulates thirst.

Question 15

What is tubular reabsorption?

Answer 15

The process of selectively moving substances from the tubular fluid back into the blood.

Question 16

What is tubular secretion?

Answer 16

The movement of substances that need to be removed from the body moving from the bloodstream into the tubular fluid that leaves the body as urine.