The Brain Flashcards
The Hindbrain
Generally for movement and balance.
Hindbrain structures link the brain to the spinal cord, sustain life by controlling the supply of air and blood to cells in the body, and regulate arousal level.
The Midbrain
Generally for hearing and vision (longer distance sensations)
The Forebrain
Generally for smell and taste (close sensations)
involved in complex sensory, emotional, cognitive and behavioural processes.
The Pons
A small hindbrain region
contains fibres that link the medulla and the cerebellum with the upper portion of the brainstem.
Also controls respiration, movement, sleep, waking and dreaming.
The Medulla
An extension of the spinal cord the links to the brain.
Essential to life, controls essential functions such as heartbeat, circulation and respiration.
Connects brain with the rest of the body.
This is where axons swap sides, making brain contralateral.
The Cerebellum
Involved in coordination of smooth, well-sequenced movements, maintaining balance and posture.
Plays a role in psychological processes as well, most importantly sensory and and cognitive processes such as learning associations.
Reticular Formation
A diffuse network of neurons that extends from the lowest parts of the medulla in the hindbrain to the upper end of the midbrain.
The reticular formation sends axons to many parts of the brain and to the spinal cord. Its major functions are to maintain consciousness, regulate arousal levels and modulate the activity of neurons throughout the central nervous system.
The reticular formation also helps higher brain centres to integrate information from different neural pathways by calling attention to their simultaneous activation.
The Tectum
In the midbrain.
Includes structures involved in vision and hearing.
These structures largely help humans orient to visual and auditory stimuli with eye and body movements.
Note–
When higher brain structures are lesioned, people can often still sense the presence of stimuli, but they cannot identify them, leading to a strange phenomenon: people may think they are blind but they can actually respond to visual stimuli
The Tegmentum
In the midbrain.
Includes parts of the reticular formation and other neural structures such as the substantia nigra.
Serves a variety of functions, many related to movement.
Plays a role in learning to produce behaviours that minimise aversive consequences and maximise rewards.
Neurons deep inside the tectum are part of a system of neurons involved in generating unpleasant feelings and linking them, through learning, to actions that can help the animal escape or avoid them.
The Hypothalamus
Situated in the front of the midbrain.
Only accounts for 0.3% of the brains weight.
This structure regulates behaviours ranging from eating and sleeping to sexual activity and emotional experience.
Works closely with the pituitary gland and provides a key link between the nervous system and the endocrine system, largely by activating pituitary hormones.
One of the most important functions of the hypothalamus is homeostasis — keeping vital processes such as body temperature, blood-sugar (glucose) level and metabolism within a fairly narrow range.
The Thalamus
Is a set of nuclei located above the hypothalamus.
Its various nuclei perform a number of functions.
One of its most important functions is to process sensory information as it arrives and transmit this information to higher brain centres.
The thalamus is like a switchboard for routing information from neurons connected to visual, auditory, taste and touch receptors to appropriate regions of the brain. However, the thalamus plays a much more active role than a simple switchboard. It not only routes messages to the appropriate structures but also filters them, highlighting some and de-emphasising others.
Note–
The thalamus is ideally situated for performing this function, since it receives projections (i.e., axons leading to it) from several sensory systems, as well as feedback from higher cortical centres in the brain. Thus, the thalamus can collect information from multiple senses and determine the extent to which information is converging on something important that may require more detailed processing.
The Limbic System
A set of structures with diverse functions involving emotion, motivation, learning and memory.
Includes the septal area, amygdala and hippocampus.
The Cerebral Cortex
consists of a 3-millimetre-thick layer of densely packed interneurons.
It’s greyish in colour and highly convoluted.
The convolutions (folds and wrinkles) of the cerebral cortex allow a relatively large area of cortical cells to fit into a compact region in the skull.
The hills of the convolutions are known as gyri (plural of gyrus) and the valleys sulci (plural of sulcus).
