Human Brain Structures & Functions
- The brain, alongside the spinal cord, is part of thecentral nervous system(CNS)
- The brain is made of billions ofinterconnected neurones
- Within the brain aredifferent regionsthat carry outdifferent functions
Different regions of the brain carry out different functions
- You need to know the functions of the following brain regions
The cerebrum
- The cerebrum is thelargest partof the brain in humans, accounting for about 80% of the total mass of the brain
- It carries out a largevariety of functionsinvolved withconscious activities, including:
- Vision
- Hearing
- Speech
- Thinking
- 内存
- The cerebrum is divided into两半known as thecerebral hemispheres
- The hemispheres are joined together by aband of nerve fibresknown as thecorpus callosum
- Theright hemispherecontrols theleft side of the bodyand theleftone controls theright side
- The cerebrum has athin outer layerknown as thecerebral cortexor 'grey matter'
- The cerebral cortex consists of thecell bodies of neurones
- It ishighly folded, whichincreases its surface areaand allows it to contain agreater number of neurones
- With more neurones in the brain,more neurone connectionscan be made
- This is important, as the more connections between neurones in the brain, thegreater the ability of the brain to carry out more complex behaviours
- Beneath the cerebral cortex or grey matter layer is the 'white matter'
- The white matter consists of themyelinated axons of neurones
The cerebrum consists of two hemispheres joined by the corpus callosum
The hypothalamus
- The hypothalamus monitorsthe bloodas it flows through the brain and, in response,releases hormonesorstimulatestheneighbouringpituitary glandto release hormones
- The hypothalamus plays an important role in somehomeostaticmechanisms
- Hypothalamus functions include
- Regulating body temperature
- The hypothalamusmonitors blood temperatureand initiates a homeostatic response if this temperature gets too high or too low
- Osmoregulation
- Cells in the hypothalamusmonitor the water balance of the bloodand releases the hormone ADH if the blood becomes too concentrated
- ADH increases absorption of water in the kidneys
- Cells in the hypothalamusmonitor the water balance of the bloodand releases the hormone ADH if the blood becomes too concentrated
- Regulating digestive activity
- The hypothalamus regulates the hormones that control appetite as well as the secretion of digestive enzymes
- Controlling endocrine functions
- The hypothalamus causes the pituitary gland to release hormones that control a variety of processes e.g. metabolism, growth and development, puberty, sexual functions, sleep, and mood
- Regulating body temperature
Pituitary gland
- The pituitary gland is locatedbelow the hypothalamus
- Its role is to produce arange of hormones
- Some of these directly influence and regulate processes in the body while some stimulate the release of further hormones from otherendocrine glands
- The pituitary gland is divided into two sections; theanterior pituitaryandposterior pituitary
- The anterior pituitary produces and releases hormones
- The posterior pituitary stores and releases hormones produced by the hypothalamus e.g. ADH and oxytocin
The cerebellum
- The cerebellumcoordinates movement
- This includesbalance;a highly complex function that requires coordination between multiple parts, including the eyes, semicircular canals in the ears, and many muscles
The medulla oblongata
- Also known as themedulla
- The medulla contains co-ordination centres that control different unconscious functions e.g.
- The cardiac centrecontrols heart rate
- The respiratory centrecontrols breathing rate
- The medulla controls functions that are able to maintain life even if other parts of the brain are damaged