Final Exam (Exam 3 stuff) Flashcards
Functions: i.Sensory 1. Somatic sensory (Se) 2. Special sensory (SS) 3. Visceral sensory (SV) ii.Motor 1. Somatic/Branchial motor (Mo) 2. Parasympathetic motor (MP)
Foramen Magnum
- exit for spinal cord
- by far the biggest hole in skull (point of herniation)
External carotids feeds what?
-the face, skull, and meninges
Pterion
- weakest poing in skull
- immediately overlies middle meningeal artery
- bleeding outside meninges can cause epidural hematoma (EDH)
Meninges (layers?)
- pia mater
- arachnoid mater
- dura mater
- spinal cord vs brain
- in spinal cord, subarachnoid space is enlarged.
Cranial arteries (location and cause of what?)
- in subarachnoid space
- cause of subarachnoid hemorrhage (SAH)
Cranial Vasculature: Anterior circulation
Internal Carotid Artery (ICA)
splits into anterior and middle cerebral arteries
Anterior Cerebral Artery (ACA)
- provides blood supply to medial brain
- most noticeable function is sensory/motor for legs
Middle cerebral artery (MCA)
- Lenticulostriate branches feed basal ganglia and internal capsule
- Distal branches feed sensory/motor to arms/face and many language areas (on dominant side, usually left)
Cranial Vasculature: Posterior circulation
-Vertebral arteries (posterior cerebral artery)
Posterior Cerebral Artery (PCA)
- visual cortex
- visual association areas
Cranial Vasculature: Veins
- Dura mater sinuses
- Cortical veins
- Bridging veins
Bridging veins cause what?
-cause subdural hematoma (SDH)
Stroke terminology
- Ischemic (blockage)
- Hemorrhagic (bleeding)
Hemorrhagic (ICH and SAH)
ICH = intracerebral hemorrhage SAH = subarachnoid hemorrhage
Blood Brain Barrier (BBB)
Passive::
1) tight junctions btwn endothelial cells
2) astrocyte foot processes
Active::
1) astrocytes pump chemical back into blood
Cerebrospinal fluid (CSF): Ventricular system
1) continuous circulation from inside ventricles down spinal cord
2) product of the inside of the original neural tube
Cerebrospinal fluid (CSF): production
1) Choroid plexus
2) Ependymal cells on inside of ventricles
Cerebrospinal fluid (CSF): Absorption
1) Arachnoid granulations
- pushes CSF back into dural sinuses (venous blood)
Monro-Kellie doctrine
- 3 things in brain (blood, brain, and CSF)
- an increase in the size of one (i.e., tumor) leads to a decrease in one of the others out the foramen magnum (i.e., blood or brain tissue)
Cushing’s triad - response to increased ICP
- Bradycardia (slow heart rate)
- Hypertension (increase blood pressure)
- Irregular breathing (hyperventilation)
Herniation
- final outcome of uncontrolled ICP
- brain herniates out foramen magnum, leading to compression of brain stem, and death
Causes of increased ICP
1) Hydrocephalus
- clogged CSF circulation leading to backup in brain
- very dangerous
2) turmors
3) cerebral edema (from trauma)
Brainstem divisions
Midbrain
Pons
Medulla
Cranial nerve: Surface anatomy
CN 1-2 on underside of brain CN 3-4 around midbrain CN 5 from side of pons CN 6-8 from under pons CN 9-12 in medulla