central nervous system - brain Flashcards
What is the nervous system?
a large network of specialised cells known as neurones that act as the body’s communication system
what does the nervous system do?
receives and interprets internal and external information and sends reactionary responses which can be voluntary or involuntary
what is the nervous system responsible for? (6)
everything, including sensation, movement, organ function, learning and memory
What can the nervous system be broken down into? (2)
central nervous system
peripheral nervous system
What are the 3 basic functions of the nervous system?
- motor function
- sensory function
- Autonomic function
How does the nervous system help motor function?
it controls our body’s ability to carry out purposeful movements (eg picking something up)
How does the nervous system help sensory function?
it carries signals to the brain to help us touch, smell, see etc
How does the nervous system help with autonomic function?
by regulating certain body processes such a breathing that happens automatically
what are the three higher functions of the nervous system?
- cognition
- emotions
- consciousness
How does the nervous system help with cognition?
it relays information to the brain, making connections that affect the way you think, learn, move, and behave.
How does the nervous system help with emotions?
your emotions stimulate very specific activities in your nervous system
How does the nervous system help with consciousness?
we get our sense of being ‘alive’ and having awareness through our sensory experiences, the information from sensory experiences are relayed via the nervous system
what is the cycle of homeostasis in the central nervous system? (4)
- there is an imbalance that is detected by receptors
- input is sent via the afferent pathway to the control centre
- output is sent via the efferent pathway to the **effector **
- the imbalance is corrected
What are the 4 main functions of the brain?
- communication centre of nervous system
- it makes us human (rational thought, creativity etc)
- Interprets nerve stimuli and effects a response
- generates more sophisticated actions as the spinal cord can produce reflex actions
what are the 4 main bones of the skull?
frontal bone
parietal bone
temporal bone
occipital bone
what is meningitis caused by?
inflammation of the meninges
what is a subarachnoid haemorrhage?
When a blood vessel bursts in the subarachnoid space, one of the main two types of stroke
What is cerebrospinal fluid formed by?
the ventricles of the brain
How much blood does the brain receive every minute?
about 15% of the total blood pumped by our hearts to the body
What are the two main vessels that supply the brain with blood?
the internal carotid and vertebral arteries
What do the internal carotid and vertebral arteries form? where?
the circle of willis at the base of the brain
what is the circle of willis?
a ring of arteries located at the base of the brain
what is the main function of the circle of willis? (2)
to provide a collateral blood flow between the anterior and posterior arterial systems of the brain
and to alternate blood flow pathways between the right and left cerebral hemispheres
What is the circle of willis designed to protect?
to protect the brain from ischaemia (loss of blood flow) and stroke in the case of vascular obstruction or damage.
What is the blood-brain barrier?
a semipermeable border between the capillary wall of blood vessels suppling the brain, and the nervous system – specifically a group of cells called astrocytes.
What do astocytes do? (3)
- they support and brace neurones
- anchor neurones to capillaries to supply them with nutrients
- They regulate the chemical environment of neurones, allowing passage from the blood to the brain tissue for some substances, but preventing others to protect the brain
How can the blood-brain barrier be a problem when it comes to medication?
it can be an obstacle in delivering drugs to the brain
what are the dural venous sinuses?
multiple venous channels (veins) within the cranial cavity, which are sandwiched between the two layers of the dura mater
What do the dural venous sinuses do?
they collect blood and cerebrospinal fluids which drain the CNS system, face and scalp into the internal jugular vein that takes it to the heart
What are the 4 main areas of the brain?
- cerebrum
- cerebellum
- brain stem
- diencephalon
what is the structure of the cerebrum?
it is the largest part of the brain, divided into two masses by a deep cleft into the left and right hemispheres
what connects the right and left hemispheres in the cerebrum and allows the two sides to communicate?
the corpus callosum
What kind of matter is the corpus callosum made up of?
a mass of white matter (nerve fibres)
What is the surface (outer layer) of the cerebrum made up of? what is it called?
grey matter (cell bodies)
the cerebral cortex
During development how does the cerebrum increase in surface area?
the cortical region rolls and folds upon itself
What does the left hemisphere of the cerebrum control? (2)
skeletal muscle on the right side of the body
tasks related to logic (eg science and maths)
what does the right hemisphere of the cerebrum control? (2)
the skeletal muscle on the left side of the body
tasks related to creativity and arts
What are the ridges in the cerebral cortex called?
gyri
what are the shallow groves that divide the lobes called?
Sulci
What is the line across the top of the cerebral cortex called?
the longitudinal fissure
What are the four lobes of the cerebral cortex?
- frontal
- parietal
- occipital
- temporal
What are the 7 functions of the pre-frontal cortex in the frontal lobe?
- decision making
- motivation
- problem-solving
- planning
- attention
- social behaviour
- impulse control
What is the motor cortex in the frontal lobe?
the region of the cerebral cortex involved in the planning, control, and execution of voluntary movements
What information does the motor cortex receive? what does the motor cortex then do
plans for complex movements from the pre-motor cortex so that it can activate the movement
What does the pre-motor cortex do?
integrates sensory information from other parts of the brain to plan complex movements to send to the motor cortex
What is Broca’s area?
a region in the inferior frontal lobe (usually found in left hemisphere) with functions linked to motor components of speech
What does Broca’s area plan?
the sequences of muscle contractions in the tongue, larynx and soft palate
What does the plans of the Broca’s area allow?
formulation of meaningful sentences
What may happen to a person with damage to Broca’s area?
they can understand language but have trouble expressing idea’s in words
What is the somatosensory cortex?
the region that receives impulses from the skin such as touch, temperature and pain
greater area of the somatosensory cortex is given to what?
areas with the greatest intensity for pain eg tongue and genitals
you have touched a hot cup with your hand, which area of your brain tells you the pain is in your hand?
the somatosensory cortex
What is the parietal lobe?
a major sensory processing hub for the brain
what are the 7 functions of the parietal lobe?
- sensation of touch - pain, temp
- information processing
- cognition
- spatial orientation
- coordination of movement
- visual perception - stereognosis (to know what something is without seeing it)
- speech
What is the occipital lobe?
he occipital lobe is the part of the brain responsible for interpreting information from the eyes and turning it into what a person sees.
what are the names of the two cortex’ in the occipital lobe?
primary visual cortex
visual association cortex
what does the primary visual cortex do?
receives visual stimuli from the eye
what does the visual association cortex do?
interpret the visual image from the primary visual cortex
What is the temporal lobe?
an area of the brain that receives and decodes sensory stimuli
what is the auditory receiving area in the temporal lobe?
the area that receives auditory stimuli including sound, pitch and frequency
What is the auditory association area in the temporal lobe?
the area that decodes sensory input and connects it to meaning
What is Wernicke’s area?
the area of the brain involved in language development and comprehension
What is the cerebellum?
the second largest part of the brain separated from the cerebrum from a transverse fissure, concerned with motor control
What kind of surface does the cerebellum have? why?
it has a highly folded surface to increase the surface area to enable a greater number of neurones
How many of the brains neurones is contained in the cerebellum?
nearly half
how is the cerebellum divided?
The cerebellum is divided into 3 lobes.
what are the 3 lobes in the cerebellum?
the anterior lobe
the posterior lobe
the flocculondular lobe
What are the anterior and posterior lobes responsible for?
subconscious aspects of skeletal muscle movement eg reflexes
What is the role of the flocculondular lobe responsible for? (3)
equilibrium, posture and balance
What is the primary function of the cerebellum?
to evaluate how well movements initiated by the cerebrum are being carried out and detect discrepancies and send feedback to the cerebrum to correct the errors
What is the cerebellums function in relation to posture and balance?
it enables us to learn skilled muscular activities such as dancing or catching a ball as it enables us to know where our body is in space
What can damage to the cerebellum result in?
a loss of coordinated movement (ataxia)
What is the diencephalon?
the central core of brain tissues surrounded by the cerebral hemispheres
what are the three parts of the diencephalon?
thalamus
hypothalamus
epithalamus
What is the basal ganglia’s responsibility?
regulation of voluntary movements at a subconscious level, without control movements are jerky and uncoordinated
What is the basal ganglia primarily linked to?
the initiation and execution of a movement and inhibition of unwanted movements
What does the thalamus do?
process all sensory information except smell
what is the hypothalamus?
a small part of the diencephalon located inferior to the thalamus that controls hormone output
what function of the brain is hypothalamus important in maintaining?
homeostasis
what, other than the central nervous system, is the hypothalamus part of?
the limbic system
what is the brain stem continuous with?
the spinal cord
