Anatomy and Physiology MCQs

People with occupations that involve standing all day are at risk of varicose veins. Why should this be true?

Veins have a larger lumen than arteries and so hold more blood which distends them.

Veins have only two tunics so their walls are more easily stretched into varicosity.

Gravity acting on blood in the legs puts stress on the vessel walls increasing the likelihood that they will stretch and distort.

When standing still, the valves stay open and blood accumulates in the leg veins.

Gravity acting on the blood in the legs of a standing person increases the strain on the walls of a vein. A weakness will lead to the walls becoming distended and the valve not operating correctly.

Author: rikazzz Comment

Skeleton and Joints

Synovial joints have all of the following features EXCEPT one. Which one?

Are surrounded by an articular capsule

Have synovial fluid filling the space between articulating bones

Have synovial membrane covering the articulating bone surfaces

Are supported by reinforcing ligaments

Articulating bone surfaces are covered by hyaline cartilage. Synovial membranes cover all other internal joint surfaces.

Author: rikazzz Comment

Gastrointestinal System

Which of the following organs is an accessory organ rather than an organ of the gastrointestinal tract?

Duodenum

Rectum

Caecum

Liver

The liver is not part of the digestive tract (chyme does not pass through it); rather, it contributes bile to the gut contents via the common bile duct.

Author: rikazzz Comment

Renal System

Under what conditions will the kidney produce concentrated urine? If:

Glomerular filtration rate is low.

Glomerular filtration rate is high.

Atrial natriuretic peptide and aldosterone are present in blood.

Antidiuretic hormone and aldosterone are present in the blood.

Aldosterone causes sodium to be absorbed from the filtrate at the DCT and collecting duct. This sets up an osmotic gradient. ADH makes the tubule more permeable to water. Hence, water can move from the filtrate into the tubule cells along the osmotic gradient.

Author: rikazzz Comment

Cardiovascular System

Which of the following will NOT increase cardiac output?

Increasing strength of contraction

Increasing stroke volume

Increasing heart rate

Increasing total peripheral resistance

If peripheral resistance increases, all else being unchanged, CO will fall.

Author: rikazzz Comment

Cardiovascular System

What is it called when plaque dislodges from a lesion in a blood vessel wall and then moves “downstream” to lodge in the capillary bed feeding the digestive tract? We call this a:

Myocardial infarction

Stroke

Pulmonary embolism

Mesenteric embolism

Mesenteric because the membrane surrounding the gut is the mesentery. An embolism is a dislodged blood clot that eventually gets trapped in a capillary.

Author: rikazzz Comment

Cardiovascular System

If the hydrostatic blood pressure at one point within a capillary is 35 mmHg while the colloid osmotic pressure of blood is 26 mmHg, what is the value of the pressure moving fluid into or out of the vessel? (a positive value indicates fluid movement out of the vessel, while a negative value indicates movement into the vessel).

35 + 26 = 61 mmHg and fluid moves from blood to the interstitial fluid

35 – 26 = 9 mmHg and fluid moves from blood to the interstitial fluid

26 – 35 = −9 mmHg and fluid moves from the interstitial fluid into blood

−26 – 35 = −61 mmHg and fluid moves from the interstitial fluid into blood

Hydrostatic blood pressure is an influence that moves fluid out of a capillary (so is +ve), while colloid osmotic pressure is an influence that moves water into the capillary (so is –ve). Hence +35–26 = 9.

Author: rikazzz Comment

Endocrine System

The hormones thyroxine and triiodothyronine contain which element?

Cobalt

Iron

Iodine

Manganese

These thyroid hormones require iodine in their molecule.

Author: rikazzz Comment

Nervous System

Which is the major type of nerve cell in the CNS?

Anaxonic