Introduction to the Brain Flashcards
What are the different parts of the brain?
- frontal
- temporal
- parietal
- occipital
- cerebellum
- brain stem
What is the difference between white and grey matter?
grey matter > contains the cell bodies, dendrites and the axon terminals where all synapses are
white matter > made up of axons which connect different parts of grey matter to each other
What are the meninges?
3 layers of membranes that protect the brain and spinal cord
1. dura mater
2. arachnoid
3. pia mater
What is the tentorium?
tent shaped duplicated fold of meningeal dura that attaches to the;
sphenoid bone > anteriorly
petrous temporal bone > laterally
squamous part of the occipital bone > posteriorly
Describe the directional terms unique to the CNS?
Rostral – toward the nose (anterior)
Caudal – toward the tail (posterior)
Dorsal – superior
Ventral - inferior
What are the 3 functional principles of the cerebrum?
- Each cerebral hemisphere receives sensory information from, and sends motor commands to, the opposite side of body
- The 2 hemispheres have different functions although their structures are alike
- Correspondence between a specific function and a specific region of cerebral cortex is not precise
What are sulci of the cerebral hemispheres?
grooves on the surface of the cerebral hemispheres
What are gyri of the cerebral hemispheres?
twisted ridges between sulci
What is the function of the gyri of the neural cortex?
increase surface area (number of cortical neurons)
What is the insula (island) of cortex?
lies medial to the lateral sulcus
What is the longitudinal fissure of the cerebral cortex?
separates cerebral hemispheres
What are lobes of the cerebral cortex?
divisions of hemispheres
Name the cerebral sulci and what they divide?
- Central sulcus
> divides anterior frontal lobe from posterior parietal lobe - Lateral sulcus
> divides frontal lobe from temporal lobe - Parieto-occipital sulcus
> divides parietal lobe from occipital lobe
What is the neuron?
The anatomic unit of the nervous system is the nerve cell or neuron
Describe the structure of the neuron?
> Each has a region known as the cell body
in addition there are several processes extending away from the cell body = the axon and the rest the dendrites
Function of dendrites in the neuron?
The dendrites branch and contact other neurons at synapses
Function of the axon in the neuron?
the axon [nerve fibre] transmits impulses away from the cell body and to other cells
Name the 4 zones of the neuron?
- Input zone – receives information from other cells through dendrites
- Integration zone – a cell body (or soma) region where inputs are combined and transformed
- Conduction zone – a single axon leads away from the cell body and transmits the electrical impulse
- Output zone – axon terminals at the end of the axon communicate activity to other cells
Name and describe the location of the lobes of the cerebrum?
- The frontal lobe
> lies under the frontal bone in the anterior cranial fossa - The temporal lobe
> lies under the temporal bone in the middle cranial fossa - The occipital lobe
> lies under the occipital bone in the posterior cranial fossa, along with the cerebellum - The parietal lobe
> lies under the parietal bone - The cerebellum (little brain)
> lies below the occipital lobe
> It has much thinner gyri than the cerebrum
What are association fibers and their different types?
Connections within 1 hemisphere
1. arcuate fibers:
- are short fibers
- connect 1 gyrus to another
2. longitudinal fasciculi:
- are longer bundles
- connect frontal lobe to other lobes in same hemisphere
What are commissural fibers?
Bands of fibers connecting 2 hemispheres:
1. corpus callosum
2. anterior commissure
3. posterior commissure
What are projection fibers?
- Pass through diencephalon
- Link cerebral cortex with:
> diencephalon, brain stem, cerebellum, and spinal cord - Internal capsule:
> all ascending and descending projection fibers
What is the corpus callosum?
is the most important landmark in the brain
> It is a bridge of axons that joins the two hemispheres and allows communication between them
> the corpus callosum folds back on itself rostrally. This region ends in the anterior commissure
What is the thalamus?
the relay station for the cortex
> it lies underneath the corpus callosum and can be seen cut across in frontal sections
> contains a complex number of different sub-nuclei.
How do the cerebral cortex and thalamus function?
> Each cortical lobe can be divided into separate functional areas within that lobe and each separate functional area of cortex has a separate thalamic nucleus
The thalamus serves as a kind of ‘secretary’ to its own cortical region
The ONLY way information can get to the cortex is via its thalamic relay or directly via cortico-cortical links
The cortex controls its own input by ‘instructing’ its thalamus on what it should allow through. There are as many cortico-thalamic outputs as there are thalamo-cortical inputs
What are cerebral ventricles?
hollow chambers in the brain filled with cerebrospinal fluid (csf)
- The thalamus lies on either side of the third ventricle
Describe the location of the cerebral ventriles?
The third ventricle is a kind of vertical slit running anter-posteriorly in the brain and it is connected above (rostrally) to the lateral ventricles and below (caudally) to the fourth ventricle
Where is the hypothalamus?
hypothalamus lies just under and anterior to the thalamus. The hypothalamus forms the lower and frontal wall of the third ventricle
Where is the brain stem located?
below the thalamus
Name the 3 parts of the brain stem?
- midbrain
- pons
- medulla
The brain stem controls which body systems?
- breathing,
- blood presure,
- sleep/waking,
- balance,
- swallowing
- vomiting
Which nerves arise from the brainstem?
All but 2 of the 22 cranial nerves
- optic
- olfactory
What are the boundaries of the fourth ventricle?
- The pons and medulla form the floor of the fourth ventricle
- The cerebellum forms the roof of the fourth ventricle.
Autonomic functions of the brainstem?
- The pons plays a critical role in respiration.
- The medulla oblongata is responsible for respiration and cardiovascular functions.
