Central Nervous System - Anatomy

The Medulla, also known as the medulla oblongata, is located in the brainstem and is responsible for maintaining vital body functions, most notably control of respiratory rate and heart rate. The pons is responsible for relaying information between the forebrain and the cerebellum. The cerebrum integrates complex sensory and neural functions. Broca's area is responsible for generating speech.

The cerebellum, located inferoposterior to the cerebrum, is the portion of the brain that controls balance and coordinated muscle movements.

The frontal, parietal, temporal, and occipital lobes are all regions of the cerebrum. Each lobe is associated with different types of processing. The frontal lobe helps with motor integration and conscious thought. The temporal lobe is associated with memory and auditory integration. The parietal lobe is responsible for somatosensory inputs. The occipital lobe houses the visual cortex.

The meninges are responsible for protecting the brain and spinal cord. The tough dura mater is the outermost layer of the meninges, while the pia mater is the delicate inner layer that lines the brain and spinal cord.

In order from the outermost to innermost layer, the meninges are: dura mater, arachnoid mater, subarachnoid space, and pia mater. The arachnoid mater and subarachnoid space create separation and cushioning between the dura mater and pia mater.

Receptive aphasia, the inability to understand language, is caused by ischemia to Wernicke's area. Wernicke's area is essential to incorporation of language and understanding. In contrast, Broca's area is used in language formation and speech. Someone with expressive aphasia, the inability to form words, has had damage to Broca's area in the inferior frontal gyrus.

The hippocampus is located in the temporal lobe and is responsible for memory formation. The amygdala is located in the brain interior and is responsible for aggression and libido. The globus pallidus is a subcortical structure that is responsible for initiating voluntary movement.

The blood-brain barrier is formed by three key structures. Tight junctions between nonfenestrated capillary endothelial cells prevents fluid and solutes from diffusing out of the capillary, as they would in the periphery. A thick basement membrane provides another layer of separation. Astrocytes interact with capillaries to mediate nutrient transfer.

Though most arterioles are surrounded by layers of smooth muscle, only capillaries interface with the blood-brain barrier.

The limbic system includes the cingulate gyrus, hippocampus, fornix, mammillary bodies, amygdala, and septal nucleus and is responsible for behavioral and emotional expression. This includes aggression, which is thought to originate from the amygdala. Spatial memory is located in the hippocampus, and is linked to behavioral expression.

The cerebellum controls posture, balance, muscle tone, and coordination of voluntary motor activity.

The posterior pituitary, or neurohypophysis, receives axons from the hypothalamus and secretes antidiuretic hormone (ADH) and oxytocin. The hypothalamus is responsible for regulation of thirst and water balance.

The other answer choices correctly match brain structures and functions.

The hypothalamus is often called the thermostat of the body. In addition to controlling body temperature, it also controls hunger, thirst, and reproductive behaviors.

The thalamus controls sensory integration. The cerebellum is associated with balance and coordination. The brain stem monitors vital activity, such as circadian rhythm, heart rate, and respiration.

The choroid plexus is a specialized region within the walls of each of the four ventricles in the brain that secretes CSF. Cisterna chyli is a part of the thoracic duct of the lymphatic system, and receives chyle from the intestines. The adrenal cortex and pineal gland secrete hormones, not CSF.

Cranial nerve X is also known as the vagus nerve. It is called "the wanderer" because it wanders from the brain stem through the neck, chest, and abdomen. Cranial nerve II is known as the optic nerve. Cranial nerve I is the olfactory nerve and cranial nerve V is the trigeminal nerve. None of the other cranial nerves exit the cranium.

The "little brain" is also known as the cerebellum. The Cerebellum is responsible for allowing people to maintain their posture and ability to move effectively. The occipital lobe processes visual stimuli, the medulla controls heart rate and breathing, and the flight or fight response is mediated by the amygdala.

The choroid plexus consists of modified ependymal cells and is found within the walls of the cerebral ventricles and secretes cerebrospinal fluid. Plasma is the extracellular matrix of the blood. Urine is produced by the kidneys. Lymph is the excess fluid drained from the cardiovascular system, and mixes with blood at the level of the subclavian veins.

The basal ganglia is a structure of the cerebrum that contains grey matter called the putamen, caudate nucleus, and globus pallidus. There are also two midbrain structures called the subthalamic nucleus and substantia nigra.

The brain and spinal cord are protected by special membranes called meninges. The meninges are made up of three membranes listed from superficial to deep: dura mater, arachnoid mater, and pia mater. Note that the cerebrospinal fluid circulates in the space between the arachnoid mater and the pia mater, called the subarachnoid space.

The fourth ventricle is connected to the third ventricle via the aqueduct of Sylvius (also known as the cerebral aqueduct). The third ventricle connects with the lateral ventricles through the interventricular foramina.

Cerebrospinal fluid is found mainly in the four ventricles, where it is produced by the choroid plexuses. The choroid plexuses consist of capillary networks surrounded by ependymal cells of the neuroglia. The arachnoid villi are small protrusions in the venous sinuses of the brain (namely the superior sagittal sinus) that allow cerebrospinal fluid to drain back into the blood.

The medulla is part of the brain stem. The brain stem includes the medulla, pons, and midbrain. The medulla contains the ascending and descending tracts that communicate between the spinal cord and brain. The nucleus gracilis and nucleus cuneatus are two important nuclei found in the dorsal side of the medulla which receive sensory fibers from the fasiculus gracilis and fasiculus cuneatus.

The two major components of the diencephalon are the thalamus and hypothalamus. The substantia nigra and subthalamic nucleus make up the basal ganglia while the midbrain and medulla are part of the brainstem.

The axon hillock is the last place where membrane potentials are summated before the generation of an action potential. The newly-created action potential travels down the axon to the axon terminal.