Mammalian Anatomy HW#--Cardiovascular, Lymphatic, and Neurons

1. __________ lymphatic vessels transport lymph to a lymph node, whereas __________ lymphatic vessels carry lymph away from a lymph node.

Afferent; efferent

**Afferent lymphatic vessels -- bring lymph into the node, the node cleans the lymph and follows the efferent lymphatic vessels

Efferent lymphatic vessels -- carry lymph away from the node

2. __________ contains mostly myelinated nerve fibers, whereas __________ contains mostly

White matter; gray matter

 **Cerebral cortex -- the outer layer of the cerebrum (the cerebral cortex ), composed of folded gray matter and playing an important role in consciousness.

White matter -- the paler tissue of the brain and spinal cord, consisting mainly of nerve fibers with their myelin sheaths.  Contains myelinated axons that run together in bundles called tracts

Gray matter -- the darker tissue of the brain and spinal cord, consisting mainly of nerve cell bodies and branching dendrites. Contains cell bodies and short, non-myelinated fibers.

3. Which of the following types of neurons serves as motor neurons for voluntary and involuntary movements?

Multipolar neurons

**motor neurons are neurons that control motor movements of the body. It takes commands from the cortex and sends the signal to the spinal cord, or to the spinal cord to the muscles. These neurons are also called multipolar neurons due to its one long axon and their short dendrites extending from the cell body.

4. Which of the following accounts for the heart sounds, "lubb-dubb"?

closing of the atrioventricular and semilunar valves, respectively

**In healthy adults, there are two normal heart sounds often described as a lub and a dub (or dup), that occur in sequence with each heartbeat. These are the first heart sound (S₁) and second heart sound (S₂), produced by the closing of the atrioventricular valves and semilunar valves, respectively.

5. Which of the following statements accurately describes the pressure in the atria and ventricles at the beginning of the cardiac cycle?

Pressure is highest in the atria and lowest in the ventricles.

 **For example, 120/80. The top number refers to the amount of pressure in your arteries during contraction of your heart muscle. This is called systolic pressure. The bottom number refers to your blood pressure when your heart muscle is between beats. This is called diastolic pressure.

6. Which of the following vessels empties into the right atrium?

Superior vena cava

 **Five great vessels enter and leave the heart: the superior and inferior vena cava, the pulmonary artery, the pulmonary vein, and the aorta. The superior vena cava and inferior vena cava are veins that return deoxygenated blood from circulation in the body and empty into the right atrium.