Anatomy of nervous system Flashcards
What are the layers that protect CNS?
- Cranium bones (joined by fibrous joints)
- Dura Mater
- Subdural space
- Subarachnoid space (with arachnoid membrane and cerebrospinal fluid)
- Pia mater
What is the purpose of CSF?
To protect brain and spinal cord by cushioning but also to provide chemical protection through highly regulated ion balance
How many ventricles in the brain?
4 in total,
(First and second are lateral) plus the central canal
What is the volume of the cranium
1.4 litre ( 0.4 litre of fluid)
What are the fluids in the brain?
- Blood
- Cerebrospinal fluid
- interstitial fluid (pia mater)
Where is CSF produced?
In the choroid plexus (walls of ventricles
What is the choroid plexus made of ?
Transporting epithelia derived from ependymal cells and capillaries
Where is CSF reabsorbed in the blood?
In villi , fingerlike projections of the subarachnoid space towards the ventricles
Where is blood-brain barrier absent?
In hypothalamus to allow for neurosecretory hormone secretion and vomiting centre of medulla which monitors blood for toxins
Explain development of the brain in embryo
Firstly nervous system consists of the neural plate which enlarges to become the neural tube. This further expands and the front part will become brain whereas the back will extend and become spinal cord.
What is lishencephaly?
A set of conditions that make the brain smooth
What does the corpus callosum contain ?
Several myelinated axons
What is frontal lobe ?
Motor cortex (voluntary)
What is parietal and occipital lobes?
Integrating centres for sensory information. Occipital for visual information
What is function of temporal lobe?
Auditory and olfactory information handling
What is the homeostatic centre in the brain?
Hypothalamus
What is one of the main function of the pituitary gland?
Secrete hormones like oxytocin and vasopressin
What is the function of the pineal gland?
Production of melatonin
What is the function of cerebellum?
Involved in movement, particularly balance and postures since it obtains information from vestibular organs in the ear and from frontal cortex
What is the function of the pons?
Plays a part in breathing reflexes
What does medulla control?
Swallowing/vomiting reflexes
What root of the spinal cord is for sensory information?
Dorsal root ganglion
What root of the spinal cord is for motor information?
Ventral root
What is neurotransmitter for somatic motor neurons?
AcetylCholine
What is receptor for somatic motor neurons?
Nicotinic ACh receptor
How many molecules does one ACh receptor bind ?
2
What type of receptor is ACh?
Pentameric
In what region of the spinal cord do sympathetic neurons originate?
From the thoracic and lumbar regions
In what region of the spinal cord do parasympathetic neurons originate?
Brain stem or sacral region
How many neurons involved in autonomic pathway?
2: One preganglionic(CNS-ganglion) and one postganglionic (ganglion-organ). These are longer in symp. and shorter in parasympathetic.
What neurotransmitter and receptor are used in ganglion of sympathetic system?
Ach to Nicotinic ACh receptor
(same as parasympathetic
)
What neurotransmitter and receptor are used in ganglion of sympathetic system?
Ach to Nicotinic ACh receptor (same as sympathetic )
What neurotransmitter and receptor are used in postganglionic part of sympathetic system?
Noradrenalin to Adrenergic receptor
What neurotransmitter and receptor are used in postganglionic part of parasympathetic system?
ACh to Muscarinic ACh receptor
What is a peculiar feature of autonomic synapse?
The presynaptic axon ends in varicosities which contain synaptic vesicles and allow for a diffused secretion of neurotransmitters in the muscle cells
