Brain structure and function:
- Cerebrum:
- Frontal lobe – motor area, personality, behavior, emotional expression, intellectual functions, memory storage
- Parietal lobe – somatosensory area especially from skin and muscle – taste – speech – reading
- Occipital lobe – vision and vision-related reflexes and such functions as reading, judging distances, seeing in three dimension, etc.
- Temporal lobe – hearing (auditory area), smelling (olfactory area), taste, memory storage, part of the speech area
- Diencephalon:
- Thalamus – relay structure and processing center for most sensory information going to the cerebrum
- Hypothalamus – integrating system for the autonomic nervous system – regulation of temperature, water balance, sex, thirst, appetite, and such emotions as fear and pleasure – regulates the pituitary gland, and controls endocrine function
- Brain Stem:
- Midbrain – relays sensory and motor information and is associated with visual reflexes
- Pons – relays sensory and motor information and plays a role in respiration
- Medulla – vital for regulating heart rate, blood flow, blood pressure, respiratory centers – the reflex center for coughing, sneezing, swallowing, and vomiting
- Cerebellum: smooths out and coordinates voluntary muscle activity, and helps in the maintenance of balance and muscle tone
- Other structures:
- Limbic system – the emotional brain controlling the experience of emotion and behavior
- Reticular formation – mediates wakefulness and sleep
- Basal nuclei – smooths out and coordinates skeletal muscle activity
Six major regions of the adult brain:
- Cerebrum is divided into large hemispheres where thought processes, sensations, intellectual functions, memory storage and retrieval, and complex motor patterns originate
- Cerebellum adjusts voluntary and involuntary motor activities according to sensory information and stored memories of previous movements.
- Diencephalon is hollow and connected to the cerebrum. The sides form the thalamus, which contains the relay and processing centers for sensory information. A narrow stalk connects the hypothalamus (the floor of the diencephalon) to the pituitary gland. The hypothalamus contains centers involved with the emotions, autonomic function, and hormone production. The pituitary gland is the primary link between the nervous and endocrine systems.
- Medulla oblongata is connected to the pons and is the segment of the brain that is attached to the spinal cord. It relays sensory information to the thalamus and other brain stem centers. It also contains major centers for the regulation of autonomic function such as heart rate, blood pressure, respiration, and digestive activities.
- Midbrain (mesencephalon) contains nuclei that process visual and auditory information and generates involuntary motor responses. This region also contains centers involved with the maintenance of consciousness.
- Pons refers to a bridge. The pons of the brain connects the cerebellum to the brain stem. This region contains tracts and relay centers and also nuclei involved with somatic and visceral motor control.The midbrain, pons, and medulla form the brain stem which contains important processing centers and relay stations for information going to or from the cerebrum or cerebellum.
Ventricles:
All joking aside, the brain IS hollow. It contains internal cavities filled with cerebrospinal fluid, and has a central passageway that expands to form four chambers called ventricles.
The largest are the two lateral ventricles located in each cerebral hemisphere. There is no direct connection between the lateral ventricles. There is an opening, however, called the interventricular foramen, that allows each of them to communicate with the third ventricle of the diencephalon.
Instead of a ventricle, the midbrain has a slender canal known as the mesencephalic aqueduct, or cerebral aqueduct, which connects the third and fourth ventricles of the pons and upper portion of the medulla oblongata. Within the medulla, the fourth ventricle narrows and becomes continuous with the central canal of the spinal cord.
See also: Brain Works Quiz
