Lecture 1 (ch 2)/ wk 1.1 Flashcards
What makes up the CNS?
The brain and spinal cord
What does the CNS arise from during embryonic development?
Arises from ecotodermal cells that fold over to form a neural tube
What are nuclei?
What are tracts?
1) Nuclei: collections of cell bodies in CNS
2) Tract: collections/ bundles of fibers in the CNS
1) What develops into the brain and spinal cord?
2) What forms ventricles?
1) Outpouchings and swellings of the neural tube develop into the brain and spinal cord
2) Fluid filled cavities form ventricles which produce CSF
1) What can cause defects of the neural tube?
2) Give examples of neural tube defects
1) Lack of folic acid during pregnancy can cause neural tube defects
2) Spina bifida, anencephaly, paralysis, bowel and bladder incontinence and hydrocephalous.
What are the 3 primary divisions of the brain?
1) Forebrain (prosencephalon)
2) Midbrain (mesencephalon)
3) Hindbrain (rhombencephalon)
1) What is the largest part of the nervous system in humans?
2) What is it subdivided into? (2 things)
3) Where is it located?
1) The forebrain
2) Telencephalon and diencephalon.
3) Sits on top of midbrain.
Name the 2 parts of the forebrain and what they consist of
1) Telencephalon: cerebral hemispheres, cerebral cortex, white matter, basal ganglia
2) Diencephalon: thalamus, hypothalamus
1) Is the midbrain long or short? What does it connect?
2) What 3 things does the hindbrain consist of?
3) What 3 things does the brainstem consist of? What does it connect?
1) Midbrain: short, connects the fore and hind brains
2) Hindbrain: pons, cerebellum and medulla
3) Brainstem: midbrain, pons, medulla; connects brain to spinal cord
What does the brainstem do? Give examples
Controls most of the basic bodily functions needed for survival.
Ex: **respirations, BP, HR
1) What two parts of the brain are important in the regulation of consciousness level?
2) What 3 things are also involved in consciousness?
3) What happens if there are lesions in these two areas?
4) What is the clinical correlation?
1) Upper pons and midbrain
2) Cortical, thalamic and forebrain networks
3) Therefore, lesions in these areas cause lethargy and coma
4) Lesions of thalami, or large lesion/s in the hemispheres/areas above brainstem) can impair consciousness indirectly through mass effect -putting pressure on the brainstem and thereby distorting or compressing its systems
1) What’s the primary function of the cerebellum?
2) What two things does the pons do?
3) What two things does the medulla do?
4) What do these 3 parts have in common?
1) Integrates sensory and other inputs from brain and spinal cord; coordinates movements from those inputs
2) Connects brain and spinal cord, and regulates level of consciousness
3) Passes information between brain and spinal cord, and regulates cardiovascular and respiratory systems
4) They’re all part of hindbrain
1) What are the 3 membranous layers of the CNS (from external to internal)
2) Where does CSF travel?
1) Dura, arachnoid and pia. 2) Between the arachnoid and pia
1) What condition can occur in the subarachnoid space?
2) What type of imaging would show this condition? What would it show is happening?
1) Subarachnoid hemorrhages occur in the CSF filled space between the arachnoid
and pia (subarachnoid space)
2) CT would reveal blood tracking down into the sulci following the contours of the pia
1) Is a subarachnoid aneurysm always a spontaneous condition?
2) What is the clinical presentation of this condition?
1) Can be either spontaneous or traumatic
2) Presentation: sudden catastrophic headache. “Worst headache of my life.” Head feels like it is ready to explode.
1) What typically causes spontaneous subarachnoid hemorrhages (SAHs)?
2) What is another potential cause?
3) What are the risk factors of intracranial aneurysms?
1) Usually caused by the rupture of an arterial aneurysm in the subarachnoid space.
2) Less often caused by other bleed at midbrain or a bleeding AVM (arteriovenous malformation)
3) Atherosclerotic disease, congenital anomalies, polycystic kidney disease, and connective tissue disorders.
1) Where do Berry aneurysms typically arise from?
2) Describe their appearance and how they’re connected to the vessel.
3) Which part of the aneurysm can rupture?
1) Arterial branch points near the Circle of Willis
2) They are balloon like outpouchings typically connected to the vessel by a stalk and
3) The dome can rupture.
1) What percent of Berry Aneurysms occur in anterior circulation?
2) What are the 3 most common locations?
1) 85% of these occur in the anterior circulation (i.e.- carotid artery and branches) most commonly:
2) Anterior communicating artery, Posterior communicating artery, and Middle cerebral artery
1) What can posterior communicating aneurysms potentially cause?
2) What are the risk factors for rupture of aneurysms?
3) What percent of patients die before the hospital? What is the overall mortality rate?
1) Painful CN III palsy.
2) Risk factors for rupture of aneurysms: HTN, cigarette smoking, alcohol consumption,
3) 25% patients die before hospital, 50% overall mortality rate
1) Which is more common, a traumatic SAH (subarachnoid hemorrhage) or spontaneous SAH?
2) How does trauma lead to a SAH?
1) Traumatic SAH more common
2) Trauma-> ruptured vessels -> blood in CSF
1) Where do subdural hematomas occur?
2) What are they typically caused by?
3) What are the two types of subdural hematoma?
1) Between dura and arachnoid
2) Typically by rupture of bridging veins
3) Chronic or acute
1) What 3 things make up the brainstem?
2) What 3 things is the brainstem connected to?
3) What arises from here? 4) What is the brainstem packed with? What do some of these things contain?
1) Midbrain, pons and medulla
2) Connected to the diencephalon, cerebellum and spinal cord.
3) Most of the cranial nerves arise from here
4) Also packed with other nuclei and white matter tracts; some nuclei contain neurotransmitters
Where do most cranial nerves arise from?
The brainstem
1) What does the brainstem do? Give examples
2) What passes through the spinal cord?
1) In charge of all vital functions needed to stay alive, ex/HR, BP, respirations; some of its nuclei contain neurotransmitters
2) ALL information passed between cerebral hemispheres and the spinal cord
1) Where do most cranial nerves (CNs) arise from?
2) Where do spinal accessory nerves arise from?
3) What do CNs do?
1) Most arise from brainstem
2) Spinal accessory nerves arise from the spinal cord
3) Have motor, sensory and other specialized functions relating to thestructures in the head
List the 12 cranial nerves in order
1) Olfactory
2) Optic
3) Oculomotor
4) Trochlear
5) Trigeminal
6) Abducens
7) Facia
8) Vestibulocochlear
9) Glossopharyngeal
10) Vagus
11) Accessory
12) Hypoglossal
What is the phrase to remember the order of the cranial nerves (CNs)?
Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly
(mnemonic from my college anatomy class)
1) Define ventral
2) Define dorsal
3) Define rostral
4) Define caudal
1) Ventral – belly, toward the earth (think venomous snake)
2) Dorsal-back, towards the sky think-shark’s dorsal fin
3) Rostral-beak, towards the snout
4) Caudal-tail, towards the tail
What is the acronym to remember whether the cranial nerves are sensory, motor, or both?
Some Say Money Matters, But My Brother Says Big Brains Matter More
1) Where does orientation change in human anatomy? Why?
2) What is the orientation of the rest of the body?
1) In humans, CNS makes 90 degree turn at midbrain, therefore, orientation above midbrain is parallel to the ground.
2) Below midbrain perpendicular to the ground
1) Define anterior
2) Define posterior
3) Define superior
4) Define inferior
1) Anterior: front
2) Posterior: back
3) Superior: top/sky-head
4) Inferior: bottom/ground-feet
1) Define horizontal/ transverse plane
2) Define coronal plane
3) Describe sagittal plane
4) Which is the most common way to view the brain?
1)Horizontal/axial/transverse: parallel to the floor
2) Coronal: perpendicular to floor, separates front and back
3) Sagittal: divides left from right
4) Sagittal
1) What is the microscopic nervous system composed of?
2) What is the basic unit of signaling? Describe its anatomy
1) Composed of neurons (nerve cells,) glia (support cells)
2) Neurons; has a cell body, which contains a nucleus, also has dendrites and an axon
1) Describe dendrites
2) Describe axons
1) Dendrites: short processes that receive inputs
2) Axons: long processes carry outputs/electrical conduction
1) Where does neuron communication occur?
2) What do chemical synapses involve?
3) Where do electrical synapses occur?
1) At synapses typically from axon to dendrite
2) Chemical: involve neurotransmitters released from 1 neuron to receptors on another
3) Electrical synapses: occur through specialized junctions
Describe action potentials
When an input excites a neuron, a transient voltage change can occur , lasts 1 ms, they rapidly move through the neuron/axon communicating with other neurons around it, can trigger release of neurotransmitters allowing further chemical communication
What are axons insulated by?
By specialized glial cells that form a fatty layer called the myelin sheath
1) Define neurotransmitters
2) Is there always only one neurotransmitter at a synapse? If not, what does it depend on?
3) True or false: Some NTs have different actions at different synapses
1) Chemicals involved in synapses
2) May have several in a single synapse depending on type of receptors present.
3) True
1) What is the most common excitatory NT in the CNS?
2) What is the most common inhibitory NT in the CNS?
3) What neurotransmitter is responsible for skeletal, smooth and cardiac muscle contractions
1) Glutamate
2) GABA (gamma-aminobutyric acid)
3) Acetylcholine
Name 4 more common neurotransmitters besides glutamate, GABA, and acetylcholine
Norepinephrine, dopamine, serotonin, and histamine
1) What makes up white matter?
2) What makes up gray matter? What occurs here?
3) Define cerebral cortex
4) What is beneath the cerebral cortex? What does it do?
1) Myelinated axons (transmit signals over some distance
2) Cell bodies; local synaptic communications between neurons
3) Gray matter that covers the cerebral hemispheres
4) The white matter that conveys messages to and from the cortex