Back to Basics - Biochem, Physiology & Anatomy

Which anatomical plane is NUMBER 2?

• Transverse

• Sagittal

• Coronal

• Astral

Answer explanation

All cells constantly undergo glycolysis to generate energy. The end result of glycolysis is the production of...

• Lactic acid

• ATP

• Glucose

• Pyruvate

Answer explanation

Note that although ATP is indeed produced during glycolysis, the process of glycolysis describes the steps in the conversion of glucose into pyruvate.

The wall of the intestines contains significant amounts of smooth muscle. Which of the following directly innervates the intestinal wall?

A) Central nervous system

B) Somatic nervous system

C) Autonomic nervous system

D) Enteric nervous system

• A, C & D

• B & C

• C & D

• D only

Answer explanation

Remember, the smooth muscles lining our internal organs ("viscera") are INVOLUNTARY and innervated by the autonomic nervous system.

The enteric nervous system is also a specialised system, specific to the gastrointestinal tract.

The somatic nervous system innervates VOLUNTARY skeletal muscles.

Cardiac troponin is a protein that is found exclusively in cardiomyocytes. Detection of troponin in the blood is an important diagnostic investigation for a heart attack. Which of the following statements about cardiac troponin is CORRECT?

• The cardiac troponin gene is in a heterochromatin state in most cells.

• The cardiac troponin gene is expressed in all cells but not translated.

• Only cardiomyocytes have the gene for cardiac troponin.

• Cardiac troponin is a housekeeping gene in cardiomyocytes.

Answer explanation

All cells in the body have the same DNA!! Differences in gene expression lead to differences in the proteins that are present.

Heterochromatin has nucleosomes that are tightly bound to each other, so genes in those areas cannot be expressed. The opposite is euchromatin.

Plasma calcium (Ca2+) levels are tightly regulated by homeostatic mechanisms. When plasma calcium levels fall, parathyroid hormone (PTH) is released by the parathyroid glands. PTH is an example of a...

• Control centre

• Effector

• Receptor

• Variable

Answer explanation

In this example, the plasma calcium is the homeostatic variable. The drop in its levels are detected by a receptor, which then causes the control centre (parathyroid glands) to release an effector (PTH) to restore the steady-state.

When an action potential reaches Point 3, ________ channels open, ________ occurs, and ________ channels close.

• Sodium, depolarisation, potassium

• Potassium, depolarisation, sodium

• Sodium, repolarisation, potassium

• Potassium, repolarisation, sodium

Answer explanation

Point 3 is at the maximum ('least negative') membrane potential. This is after depolarisation which is caused by the influx of Na+ ions.

Now, Na+ channels close while K+ channels open to allow the efflux of K+ ions. The movement of positive ions out of the cell causes the membrane potential to be repolarised ('more negative').

The hamstrings muscles are FLEXORS of the knee, while the quadriceps muscles EXTENSORS of the knee. Hamstrings muscles are commonly injured in athletes during sprinting when the leg is stuck out straight - what type of CONTRACTION are the hamstrings doing?

• Concentric contraction

• Eccentric contraction

• Isometric contraction

• Relaxation

Answer explanation

Straightening out the leg involves EXTENSION of the knee joint.

The quadriceps muscles are concentrically contracting during this movement, while the hamstrings eccentrically contract to resist and control it.

The pleural membranes of the lungs and chest cavity require lubrication to allow for frictionless breathing. Which of the following tissue would be found in these membranes?

• Mucosal

• Serosal

• Submucosal

• Subserosal

Answer explanation

Do not worry about the info in this image! You'll learn it :)

Serosal/serous membranes secrete lubricating fluid that allows structures to move against each other (found around the heart, lungs, abdomen etc.)

Mucosal/mucous membranes secrete mucous to protect us from the environment (e.g. respiratory tract, gastrointestinal tract).

Submucosal and subserous tissues do not form membranes.

Which of the following changes would you expect to occur when the parasympathetic nervous system is activated?

• Slowing of heart rate

• Increased rate of digestion

• Dilation of the pupils in the eyes

• Slowing of respiration rate

Answer explanation

If you are being chased by an axe murderer in the woods, you want to be able to see what's in front of you!

Remember, the parasympathetic nervous system makes you 'rest and digest' (an oversimplification but still useful). This would cause the pupils to constrict as there is no need to optimise your eyesight.

This soccer player is preparing to kick the ball. What movement(s) is he doing with the specific body parts in question? (RK = right knee; LA = left arm)

• RK extension, LA abduction

• RK flexion, LA adduction

• RK flexion, LA abduction

• RK extension, LA adduction

Answer explanation

The player is bending his right knee, and raising his left arm laterally. If you have trouble remembering the names of these movements, practice them on yourself by moving around! :)