THE CNS + BRAIN Flashcards
What are the two parts the PNS is divided into?
- Somatic NS (voluntary)
- autonomic (involuntary)
How many cranial nerve pairs are there?
12
How many spinal nerve pairs are there?
31
How long is the spinal cord
~45cm
What are the segments of the spine and how many vertebrae are in each?
Cervical - 7
Thoracic - 12
Lumbar - 5
Sacral - 5
Coccyx - 4
What segment of the spinal cord is responsible for breathing
C1-C4
What is the breakdown of spinal nerves?
C-8
T-12
L-5
S - 5
C- 1
Where is a lumbar puncture preformed?
Below L2
- spinal cord ends around L2
- meninges containing CSF extend further
What are the parts of the spinal cord?
- Dorsal Root
- Ventral Root
- grey matter
- white matter
What is the function of the dorsal root?
Carries sensory (afferent) info to CNS
What is the function of the ventral root?
Carries motor (efferent) into to muscles/glands
What is the function of grey matter in the spinal cord?
Consists of sensory and motor nuclei
What is the function of white matter in the spinal cord?
Consists of axons carrying into to/from the brain
What is the function of white matter in the spinal cord?
Consists of axons carrying into to/from the brain
What is the function of ASCENDING TRACTS in white matter?
Carry sensory info to the brain
What is the function of DESCENDING TRACTS in white matter?
Carry commands to motor neurons
What is the main difference between parasympathetic and sympathetic nervous system?
Sympathetic prepares body for stressful situations
Parasympathetic encourages a state of calm and conservation of energy
EG:
PARASYMPATHETIC: decreases HR and BP
SYMPATHETIC: increases HR and BP
What is the origin and role of the phrenic nerve?
Originates from C3,C4,C5
Has a crucial role in respiratory function controlling the diaphragm for breathing
How much does the brain weigh?
~1.3kg
What is a synapse?
Junction between two neurons that allow signals to pass between them
What are the major parts of the brain?
Cerebrum
Cerebellum
Diencephalon
Brain stem
What are the parts of the neuron?
Soma
Axon
Myelin
Tell me about the cerebrum?
Front of brain
RESPONSIBILITIES:
(Basically everything)
- co-ordination/movement
- speech
-temp regulation
- thinking and reasoning
- emotions
-learning
- problem solving
What is the cerebral cortex?
Outer grey matter covering the cerebrum
What is matter grey/white
(This is kinda just a nice to know)
Grey matter has no myelin (fatty covering) which gives the white colour on scan
What is the brain stem and what are the parts?
- connects cerebrum with spinal cord *
-midbrain (mescephalon)
- pons
- medulla
Tell me about the midbrain?
AKA mescephalon
RESPONSIBILITIES:
- motor control
- sensory processing
- visual reflexes
¡Rich in dopamine neurons - affected by Parkinson’s!
Tell me about the Pons
- Connects midbrain to medulla
- origin for 4/12 cranial nerves
RESPONSIBILITIES: - tear production
- chewing
- blinking
- balance
- hearing
Tell me about the medulla?
Where the brain meets the spinal cord
- essential to survival/reflex activities
RESPONSIBILITIES:
- HR
- Breathing
- Blood flow
- central chemoreceptors
- sneezing/vomiting/swallowing/coughing
Tell me about the cerebellum?
RESPONSIBILITIES:
- co-ordinate voluntary movements
- posture
- balance
- equilibrium
What is the function of the meninges?
Protective layer of brain and spinal cord
Layers of the cranial meninges?
DURA MATER- outer
passage of arteries and veins to supply blood
ARACHNOID - middle
(CSF between)
PIA MATER - hugs brain 🥺 (rich in veins and arteries)
What are the lobes of the brain?
Frontal
Parietal
Occipital
Temporal
What is the function of the frontal lobe?
- personality
- decision making
- movement
- recognition of smell
contains Broca’s area = speech ability
What is the function of the parietal lobe?
Proprioceptive stimuli - relation of one’s body compared to objects in space
contains wernickes area = understand spoken language
What is the function of the occipital lobe?
Vision
What is the function of the temporal lobe?
Short term memory/speech/musical rhythm
What is the function of the pituitary gland?
Releases hormones essential for homeostasis
What is the function of the hypothalamus?
Links nervous system to endocrine system via the pituitary gland
-temp regulation
What is the function of the amygdala
Part of the limbic system
Regulates emotion and memory
“Fight or flight”
What is the role of the hippocampus?
Memory/learning/navigation/perception of space
role in Alzheimer’s
What is the function of the pineal gland?
Responds to light/dark
Secretes melatonin - cicadium cycle
What is the function of the pineal gland?
Responds to light/dark
Secretes melatonin - cicadium cycle
What is the function of cranial ventricles and CSF
Ventricles manufacture CSF
CSF cushions the brain and spinal cord
- washes out waste and delivers nutrients
How is blood supplied to the brain?
Vertebral and carotid arteries
Vertebral arteries join together in brain stem and form basilar artery
What is the circle of Willis
Anastomotic arterial ring @ base of brain
Provides connection between 4 main arteries in brain
What is a toxidrome?
Specific collection of signs and symptoms due to toxic effects of chemicals in the body
What is a toxic effect?
Undesirable but often unavoidable adverse effects caused by excessive pharmacological action of the drug
What are the types of asphyxiants?
Simple: displace oxygen from the lungs
Systemic: interfere with oxygen transport
What are the effects of acute exposure to solvents, anaesthetics, or sedatives (SAS) toxidrome?
CNS depression leading to decreased level of consciousness, depressed respirations, and in some cases ataxia (difficulty walking/balancing)
What is an anticholinergic toxidrome?
A drug that blocks the actions of the neurotransmitter ACETYCHOLINE
Inhibits nerve impulses responsible for involuntary muscle movements and bodily functions
Used to treat overactive bladder, COPD, Parkinson’s
What are the effects of anticholinergic toxidrome?
- increased HR/BP
- increased temp
- dilated pupils
- decreases sweating
What are cholinergic drugs?
Drugs that enhance/mimic the action of the neurotransmitter ACETYCHOLINE
Used to treat nausea, urinary retention, cardiac arrhythmias etc
What are the cholinergic toxidromes?
- decreases pupils
- increased sweating
What are the opioid toxidromes?
- decreases HR/BP
- decreases RR
- decreased temp
- decreased pupils
- decreased sweating
What are sympathomimetic drugs?
Adrenaline/ cocaine ❄️/ amphetamines
What are the sympathomimetic toxidromes?
- increased everything baby
(Big zoomies)
What are the sedative-hypnotic toxidromes?
- decreased everything
(Pupils the same?)
What is organophosphate poisoning?
Organophosphates (OP) for the bases of many insecticides/herbicides
Patients can die of acute cholinergic syndrome
REMEMBER: SLUDGE
S- salivation
L- lacrimation
U- urination
D- diarrhoea
G- GI upset
E- emesis
Opening in the base of the skull where the brain is attached to spinal cord
Foramen magnun
Opening in the base of the skull where the brain is attached to spinal cord
Foramen magnun
C1 and C2 are known as what?
Atlas and axis
How many ventricles are there
4
How much CSF is in the body?
150mls
What regulates temperature in the brain?
Hypothalamus
