the nervous system Flashcards
What are the two parts of the nervous system?
- Central Nervous System
- Peripheral Nervous System
What does the peripheral NS divide into?
- The afferent NS (sensory)
- The efferent NS (motor)
What does the efferent NS divide into?
- The somatic NS (controlled)
- The autonomic NS (automatic)
What does the autonomic NS divide into?
- The sympathetic NS (fight or flight)
- The parasympathetic NS (rest & repair)
What does the central NS divide into?
- The brain
- The spinal cord
What are the parts of the brain?
- Cerebrum
- Cerebellum
- Brain stem
- Diencephalon
What are the parts of the brain stem?
- Medulla
- Pons
- Midbrain
What are the parts of the Diencephalon?
Thalamus
- Hypothalamus
- Epithalamus
What are the meninges?
inner protective covering of the brain and spinal cord (outer part of the brain)
What are the three layers of the meninges?
- Dura mater
- Arachnoid mater
- Pia mater
Describe the Dura mater.
- Outermost layer
- Strong white fibrous connective tissue
- forms inner periosteum of the cranial bones
Describe the Arachnoid mater.
- Delicate (cobweb like) middle ‘cushion’ layer
-Smooth - Cerebrospinal fluid in the subarachnoid space cushions the brain
Describe the Pia mater.
- Innermost transparent layer directly covering brain and spinal cord
- follows brain’s wrinkles
- has blood vessels- brain bleed
What are the three main meninges-related spaces?
- Epidural space
- Subdural space
- Subarachnoid space
Describe the epidural space
between dura matter and bony coverings in spinal cord- cushioning function with fat and connective tissue
Describe the subdural space
between dura mater and arachnoid mater- lubricating function with serous fluid
Describe the subarachnoid space
between arachnoid mater and pia mater- cushioning function with lots of cerebrospinal fluid
Where is cerebrospinal fluid made?
Choroid plexuses from blood plasma by ependymal cells
What is cerebrospinal fluid?
- Cushioning fluid protecting the brain and spinal cord
- found in subarachnoid spaces and cavities/canals
How much cerebrospinal fluid is there?
about 140ml
- 117 in subarachnoid spaces
- 23 in CSF ventricles
What does the cerebrospinal fluid monitor?
Change in the internal environment
- CO2 levels
- triggers hypothalamus
What does interference with CSF flow cause (tumor)
Build up of pressure on nervous tissue -> damage -> coma or death
What is the largest division of the brain?
The cerebrum (83% of brain mass)
Describe the cerebrum
- Largest brain division
- 4 lobes (5th small lobe)
- Has elevated ridges (gyri and sulci)
- White matter inside, grey outside
- Basal nuclei are deep inside
What is the function of the cerebrum?
- Sensory and motor functions
- 47-52 functional ‘Brodmann areas’ in the cortex
- touch, pressure, temperature, body position, vision, hearing, intelligence, learning, memory
What area of the brain is responsible for speech?
Broca’s area of the frontal lobe of the cerebrum
What is the left hemisphere of the cerebrum involved in?
language and gestures
What is the right hemisphere of the cerebrum involved in?
auditory stimuli (crying, laughing, music
Where is the diencephalon located?
Between the cerebrum and midbrain
What are three important structures of the diencephalon?
thalamus, hypothalamus, epithalamus
Describe the thalamus
- receives incoming sensory impulses
- regulates sleep (damage -> coma)
- Produces sensations and their associations
- arousal
What is the hypothalamus referred to as?
The survival and pleasure centre