Help with Brain Physiology - Anatomy

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.

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 medulla oblongata is part of the brainstem. It has chemoreceptors to detect changes in blood gasses, which is integrated and transformed via negative feedback by altering respiratory rate and aspects of cardiac function such as heart rate and cardiac output via the autonomic nervous system. Many reflexes are also carried out by the medulla including vomiting, coughing, sneezing, and swallowing. The hypothalamus regulates many other homeostatic parameters such as hunger, basal body temperature, circadian rhythm, thirst, fatigue, in addition to acting as the "master" of the pituitary gland, which secretes several hormones.

The corpus callosum is the band of myelinated fibers which connects the two cerebral hemispheres. Sulci is the general term for the grooves "valleys" in the brain. The cerebral aqueduct (aqueduct of Sylvius) carries cerebrospinal fluid from the third ventricle to the fourth ventricle. The longitudinal fissure is the deep groove that separates the left and right hemispheres of the brain. The lateral sulcus separates the frontal and parietal lobes of the brain from the temporal lobe.

Broca's area (motor speech area) is located in the left hemisphere of the frontal lobe. Broca's area controls all activities associated with speech production, including articulation and facial expression. However, recently it has been suggested that it also plays significant roles in speech comprehension. This is not to be confused with Wernicke's area, which is also in the left hemisphere of the frontal lobe, but is more associated with speech comprehension than speech production.

The bundle of fibers that connects Wenicke's area with Broca's area is called the arcuate fasiculus. Broca's area is located in the frontal lobe and Wernicke's area is located in the temporal lobe. The corpus callosum is a band of nerve fibers that connects the left and right hemispheres of the brain. The Aqueduct of Sylvius is a canal which cerebrospinal fluid flows between the third and fourth ventricles of the brain. The lateral sulcus is a prominent structure in the brain which divides the frontal lobe and parietal lobe (above) from the temporal lobe (below), while the central sulcus separates the frontal lobe from the parietal lobe.

Knowing how to ride a bike is an example of procedural memory. Procedural memory is involved in learning motor skills. Working memory can be another name for immediate memory, which means lasts a few seconds to a few minutes, such as temporarily remembering a set of numbers. Declarative memory includes short-term memory and is concerned with people, events, occurrences, and facts.

The hypothalamus (part of the diencephalon) is responsible for maintaining the sleep-wake cycle and regulating the "biological clock". These are set by a specific nuclei located in the hypothalamus, the suprachiasmatic nucleus. The thalamus is also part of the diencephalon but is primarily involved in relaying sensory and motor signals through the cerebral cortex. The thyroid is an endocrine gland which secretes thyroid hormones that regulate metabolism, growth and development, and temperature. The cerebellum coordinates muscle activity and the basal ganglia aids in coordinating movement. The epithalamus contains the pineal gland, which may play a role in the sleep-wake-cycle (circadian rhythm) via the hormone melatonin.

The brainstem consists of the midbrain, pons, and medulla oblongata. The brainstem continues inferiorly to become the spinal cord. The brainstem is responsible for basic living functions, including but not limited to: respiration, circulation (including heart rate), and digestion. As such, any injury to the brainstem would be catastrophic. Additionally ten of twelve cranial nerves pass through the brainstem, going on to provide the face and neck with motor and sensory functions. Furthermore, nerve conduction of the motor and sensory systems of the brain and body pass through the brain stem including the corticospinal tract (involved in motor activity), the posterior column-medial lemniscus pathway (involved in fine touch, vibration sensation, and proprioception), and the spinothalamic tract (involved in pain, temperature, itch, and crude touch).