INTS 6: Introduction to Nervous and Musculoskeletal Systems Flashcards
What is the nervous system?
What is the nervous system comprised of?
Very briefly describe their function
- central nervous system (CNS) :
- brain
- spinal cord
- peripheral nervous system (PNS) :
- cranial peripheral nerves
- spinal peripheral nerves
- these help carry out sensory and motor functions
Where do cranial nerves arise from?
- the brain and brainstem
Where do spinal nerves arise from?
- the spinal cord
What type of neurons are most cranial and all spinal nerves made up of?
- they are made up of axons of both motor and sensory neurons
What pathways does the PNS use to send/relay information?
- relaying information back to CNS:
- sensory/afferent/ascending pathways
- sending information from CNS to the rest of the body:
- motor/efferent/descending pathways
- motor pathways can be further divided into somatic (voluntary) and autonomic (involuntary) components
- observe diagram
Observe the diagram and define these orientation terms
- ventral and dorsal change along the course of the nervous system
- rostral:
- anything toward the anterior pole of the brain
- caudal:
- anything toward the inferior pole of the spinal cord
Observe this diagram of the different planes of orientation
- this will be further explained in later sessions
What is the part of the CNS housed within the cranial cavity called?
- the brain
Describe the surface features of the brain
- ridges: called gyri
- grooves: called sulci
- larger grooves: called fissues
Describe the divisions of the brain
- comprised of the forebrain:
- cerebral hemispheres
- hypothalamus
- thalamus
- midbrain
- hindbrain:
- pons
- medulla
- cerebellum
Describe the lobes the cerebral hemispheres are divided into
- frontal
- parietal
- occipital
- temporal
- limbic
- insular
How much of the body’s blood supply does the brain receive?
Compare it to the weight
- 15-20 of the body’s blood supply
- whereas it’s 2% of total body weight
Which two principal sources supply blood to the brain?
Where is the source of these sources?
- internal carotid arteries
- vertebral arteries
- these arteries are indirect or direct branches of the main artery from the heart, the aorta
Describe the Circle of Willis
How do the internal carotid and vertebral arteries supply blood to the brain?
- The internal carotid arteries ascend in the neck and enter the cranial cavity through holes (foramina) in the skull
- The vertebral arteries, as the name suggests, are associated with the bones in the neck, the vertebrae
- The two vertebral arteries join to form the basilar artery, this vertebral-basilar system supplies the brainstem and spinal cord.
- The forebrain receives blood from both the internal carotid and vertebral-basilar systems, which join to form an arterial circle at the base of the brain - the Circle of Willis.
Where do the anterior, middle and posterior cerebral arteries supply?
- The anterior cerebral arteries:
- supply the medial surfaces of the front two thirds of the cerebral hemispheres
- the middle cerebral arteries (extensions of the internal carotid arteries):
- supply most of the lateral surfaces of the brain as well as deep structures
- the posterior cerebral arteries:
- supply the medial surfaces of the posterior one third of the forebrain
What subdivisions form the autonomic nervous system?
- parasympathetic:
- rest and digest
- under ‘normal’ circumstances
- sympathetic:
- fight or flight
- when are body is put into a stressful situation
What are some responses from
- parasympathetic system
- sympathetic
What do sensory neurons do?
- relay information toward the CNS