Brent Cornell

    
The human brain acts as an integration and coordination system for the control of body systems

• It processes sensory information received from the body and relays motor responses to effector organ

The human brain is organised into clearly identifiable sections that have specific roles

• The major external structures include the cerebral cortex, cerebellum and brainstem
• Internal structures include the hypothalamus, pituitary gland and corpus callosum

External Structures

Cerebral Cortex

• The cerebral cortex is an outer layer of tissue organised into two cerebral hemispheres and composed of four distinct lobes
• The frontal lobe controls motor activity and tasks associated with the dopamine system (memory, attention, etc.)
• The parietal lobe is responsible for touch sensation (tactility) as well as spatial navigation (proprioception)
• The temporal lobe is involved in auditory processing and language comprehension
• The occipital lobe is the visual processing centre of the brain and is responsible for sight perception

Cerebellum

• The cerebellum appears as a separate structure at the base of the brain, underneath the cerebral hemispheres
• It is responsible for coordinating unconscious motor functions – such as balance and movement coordination

Brainstem

• The brainstem is the posterior part of the brain that connects to the spinal cord (which relays signals to and from the body) 
• The brainstem includes the pons, medulla oblongata (often referred to as the medulla) and the midbrain
• The brainstem (via the medulla) controls automatic and involuntary activities (breathing, swallowing, heart rate, etc.) 

External Structures of the Brain

    
Internal Structures

Hypothalamus

• The hypothalamus is the region of the brain that functions as the interface with the pituitary gland
• As such, the hypothalamus functions to maintain homeostasis via the coordination of the nervous and endocrine systems
• The hypothalamus also produces some hormones directly, which are secreted via the posterior pituitary (neurohypophysis)

Pituitary Gland

• The pituitary gland is considered the ‘master’ gland – it produces hormones that regulate other glands and target organs
• The anterior lobe is called the adenohypophysis and secretes hormones such as FSH, LH, growth hormone and prolactin
• The posterior lobe is called the neurohypophysis and secretes hormones such as ADH and oxytocin

Corpus Callosum

• The corpus callosum is a bundle of nerve fibres that connects the two cerebral hemispheres
• It is the largest white matter structure in the brain, consisting of roughly 250 million axon projections
• Damage to the corpus callosum can prevent information exchange between left and right hemispheres (split brain disorders)

Internal Structures of the Brain