1. Which of the following is principally involved in internal communication within the body?
A. The special senses.
B. The respiratory system.
C. The reproductive system.
D. The endocrine system

2. Blood does NOT contain:
A. Plasma.
B. Chromosomes.
C. Platelets.
D. Erythrocytes.

3.Which cells do NOT have nuclei?
A. Skeletal muscle cells.
B. Red blood cells.
C. White blood cells.
D. Columnar epithelial cells.

4. The process of cell division which produces gamete cells is called:
A. Mitosis.
B. Transcription.
C. Meiosis.
D. Budding.

5. Hemoglobin is a?
A. Protein.
B. Carbohydrate.
C. Antibody.
D. Blood cell


6. An artery that provides the only blood supply to a tissue is called a(n):
A. End artery.
B. Anastomotic artery.
C. Shunt.
D. Arteriole.

7. Which of the following describes the cluster of blood capillaries found in each nephron?
A. Afferent arteriole.
B. Loop of Henle
C. Renal tubule
D. Glomerulus

8. The atrioventricular node:
A. Sets the normal heart rate.
B. Generates electrical signals, but at a faster rate than the sinoatrial node.
C. Controls blood flow between the atria and the ventricles.
D. Acts as the heart’s secondary pacemaker.

9. Lymph and plasma:
A. Are identical in composition.
B. Are very similar in composition, although plasma contains fewer plasma proteins.
C. Are very similar in composition, although lymph contains no white blood cells.
D. Are very similar in composition, although lymph may contain cell debris.

10. At the synapse:
A. The presynaptic neuron has one large synaptic knob.
B. Neurotransmitters are made just before they are required not stored.
C. Neurotransmitters diffuse across the synaptic cleft and can only act on specific receptor sites.
D. Neurotransmitters always have an excitatory effect on the postsynaptic membrane.