CNS- Brain And Spinal Cord Flashcards
What is the function of the brain?
Where info from the internal/external environment is processed
What are the 3 major regions of the brain?
Cerebrum, cerebellum and brain stem
What is the function of the cerebrum?
Largest/most developmentally advanced part of the brain
Responsible for several higher function eg higher intellectual function, speech, integration of sensory stimuli of all types and fine control of movement
What is the function of the cerebellum?
Second largest area
Responsible for maintaining balance/posture and further control of movement/coordination
What is the function of the brain stem?
Responsible for variety of automatic functions eg control of respiration, HR, BP, wakefulness, arousal and attention
Autonomic functions
Divided into medulla, midbrain and pons
What is the corpus callosum?
Band of white matter consisting of a bundle of several million nerve fibres/axons
Allows communication between 2 cerebral hemispheres
What is the function of the cerebral cortex?
Area of conscious thought and perception
What are the 4 lobes of the cerebral cortex?
Frontal, parietal, occipital and temporal lobes
What is the function of the frontal lobe?
Personality, emotions, motor, speech, memory and movement
What is the function of the parietal lobes?
Auditory association
Interpretation of words and thoughts, olfactory area, and interpretation of smell
What is the function of the temporal lobe?
Speech, language, smell, touch, position sense
Interpretation of sensation, spatial awareness and storage of sensory experience
What is the function of the occipital lobe?
Sight/visual interpretation
Past visual experience
What is the sensory cortex?
Situated in the parietal lobe
Receives and processed sensory info throughout the body
Transmitted here via sensory neurones from sensory organs eg skin, eyes
What is the motor cortex?
Located in the frontal lobe
Responsible for planning, control and voluntary movement
What is the limbic system?
Complex set of structures lying on both sides of the thalamus just under the cerebellum
What makes up the limbic system?
Hypothalamus
Hippocampus
Amygdala
What is the function of the limbic system?
Responsible for our emotional life
Formation of memories
Detecting changes in the internal environment
What is the function of the amygdala?
Involved in many of our emotions and motivation- related to survival eg fear, anger etc
What is the function of the hippocampus?
Involved in conversion of recent memories into long term memory
What is the function of the midbrain?
Uppermost part of brain stem
Contains auditory and visual reflex centres
Controls cranial reflex activities eg blinking
What is the function of pons?
Meaning bridge- lies between midbrain and medulla oblongata eg medulla
Relays sensory info between the cerebrum and cerebellum
What is the function of the medulla oblongata?
Contains respiratory, vasomotor and cardiac centres for control of breathing and cardiovascular function
Many mechanisms for controlling reflex activities eg coughing, gagging, swallowing and vomiting
What is the function of the spinal cord?
Links the brain to the rest of the body
Stretches from the medulla oblongata to the level of the 2nd lumbar vertebrae and runs inside the vertebral canal
Where are the sensory and motor nerve fibres found?
Sensory nerve fibres- ascending tracts in SC
Motor nerve fibres- descending tracts in SC
What 4 factors protect the brain?
1) cranium (skull)
2) meninges (membranes)
3) cerebrospinal fluid
4) blood-brain barrier
What is the function of the meninges?
Membranes around CNS providing another layer of protection- surround brain and spinal cord
3 distinct layer:
1) dura mater- outermost layer- thick/strong
2) arachnoid mater- middle layer- thin/transparent membrane
3) pia mater- innermost layer- delicate/follows brain and SC surface
What is the blood brain barrier?
Formed by tight junctions of capillaries and astrocytes (type of glial cells)
Numerous projections- Foot processes- encircle capillary and great semi-permeable membrane, separating blood from neurones in the brain
Offers protection from toxic substances
Also difficult to get some drugs into the brain
What does the blood brain barrier stop?
1) most chemicals in blood entering brain eg antibiotics
2) proteins
3) NT leaking out into circulation
What does the blood brain barrier not stop?
1) oxygen
2) carbon dioxide
3) most anaesthetic agents
4) few water soluble substances eg glucose
5) alcohol
6) urea and creative (crossing much more slowly)
What is cerebrospinal fluid?
Clear fluid containing glucose, proteins, lactic acid, urea and WBC
Produced by ependymal cells (type of glial cell) in choroid plexuses of the ventricles in the brain/ canal of the SC
Helps protect brain and SC
What are the functions of CSF?
Contributes to intracranial pressure
Provides medium so nutrients and waste products can be exchanged
Supports weight of brain- ‘float’ in the skull
