Intro to brain video Flashcards
What are four major regions of the brain
Four major regions:
* cerebrum
* diencephalon
* brainstem
* cerebellum
Where to crainial nerves orginate
- cerebrum
- diencephalon
- brainstem
- cerebellum
Mainly brainstem
What are three main areas of brainstem
Midbrain,Pon,Medulla oblengata
The prosencephalon goes on to form what two secondary brain vesicles?
Telencephalon and diencephalon
What is grey matter?
color from motor and interneuron cell bodies, dendrites, and unmyelinated axons
Where is gray matter located within the cerebrum? Within the spinal cord?
In the cerebrum the grey matter covers the surface of the brain. It is also present in small clusters inside the white matter.
What is white matter?
- color from myelin on axons
What are the protections of the brain?
- Membranes (meninges)
- Ventricles
- Watery cushion (cerebrospinal fluid)
- Blood-brain barrier
What is function of Meninges?
- Cover and protect the CNS
- Protect blood vessels and enclose venous sinuses
- Contain cerebrospinal fluid (CSF)
- Form partitions in the skull
What are three layers of Meninges?
- Dura mater
- Arachnoid mater
- Pia matter
What is dura matter?
Two layers of fibrous connective tissue (around the brain) separate to form dural sinuses
What is arachniod matter?
- Middle layer with weblike extensions
- Separated from the dura mater by the subdural space
- Subarachnoid space contains CSF and blood vessels
- Arachnoid villi protrude into the superior sagittal sinus and permit CSF reabsorption
What is pia matter?
Layer of delicate vascularized connective tissue that clings tightly to the brain
From superficial to deepest, name the meninges and the spaces between them.
Dura mater, subdural space (potential space), arachnoid mater, subarachnoid space, pia mater
What are ventricles of the brain?
- Connected to one another and to the central canal of the spinal cord
- Lined by ependymal cells
What are the division of the ventricles?
- Contain cerebrospinal fluid
- Two C-shaped lateral ventricles in the cerebral hemispheres
- Third ventricle in the diencephalon
- Fourth ventricle in the hindbrain, dorsal to the pons, develops from the lumen of the neural tube
What is composition of cerebrospinal fluid?
Composition
- Watery solution
- Less protein and different ion concentrations than plasma
- Constant volume
What is function of Cerebrospinal Fluid?
Functions
- Gives buoyancy to the CNS organs
- Protects the CNS from blows and other trauma
- Nourishes the brain and carries chemical signals
How is cerebrospinal fluid formed?
- Formed by choroid plexus
- specialized tissue in each ventricle
- layer of ependymal cells and blood capillaries (within pia)
- Produced by secretion from ependymal cells
- Originates from blood plasma
- Composition somewhat similar to plasma
What are the three main functions of cerebrospinal fluid?
It provides buoyancy, protection, and environmental stability to the brain.
Where is CSF first produced? How does excess CSF get removed from the blood?
It is first produced by the choroid plexus in the ventricles.
It is removed from the blood after flowing into the arachnoid villi, which drain into the dural venous sinuses.
What is Function of blood brain barrier?
- Strictly regulates which substances enter brain’s interstitial fluid
- Helps prevent neuron exposure to harmful substances
- e.g., drugs
- blood waste products
- variations in levels of normal substances
- e.g., ions, hormones
What is composition of blood brain barrier?
Blood-brain barrier composition
- Most capillaries in brain wrapped by perivascular feet
* astrocyte extensions
- Endothelial cells and perivascular feet both contributing to BBB
- Continuous basement membrane of endothelial cells
- Tight junctions between adjacent endothelial cells
* reduce capillary permeability
- Astrocyte “gatekeepers” controlling materials leaving neurons
What components make up the blood-brain barrier?
Capillary endothelial cells (with tight junctions), basement membrane, perivascular feet of astrocytes
