Overview of the Nervous System Flashcards
What are the three orientations of scans?
-sagittal - Divides brain into left and right
-coronal (frontal) - Divides brain into anterior and posterior portion
-transverse - Bisects brain horizontally, allowing for superior view
What are the 3 major brain regions?
- the FOREBRAIN (made up of the cerebrum and the diencephalon)
- the BRAINSTEM (made up of the midbrain, the pons and the medulla oblongata)
- the CEREBELLUM
List the 4 lobes of the cortex.
- the frontal lobe
- the occipital lobe
- the parietal lobe
- the temporal lobe
List the roles of the frontal lobe, and give evidence of that.
Roles:
- decision making
- attention
- consciousness
- voluntary movement
- behaviour
Evidence:
- a prefrontal lobotomy used to be a normal procedure for cognitive disorders, but it often resulted in impaired voluntary behaviour
List the roles of the occipital lobe, and give evidence of that.
Roles:
- visual processing and interpretation (eg. colour, orientation, motion)
- Distance and depth perception, colour, object and face recognition
Evidence:
- McCarley et al., (1999) examined MRI data from patients with schizophrenia and found abnormal activity levels in their occipital lobes.
List the roles of the parietal lobe, and give evidence of that.
Roles:
-sensory processing and interpretation (i.e touch)
- proprioception (i.e. equilibrium and balance of the body)
Evidence:
- reduced levels of activation have been detected in the left parietal lobe of people with dyslexia (Pammer, 2014)
List the roles of the temporal lobe, and give evidence of that.
Roles:
- auditory processing and interpretation
- language
- speech
- Memory (e.g. formation of long-term memories)
Evidence:
- in 1874, Carl Wernicke hypothesised a link between a discrete area of the temporal lobe and receptive aphasia. Receptive aphasia is a condition where there is a major impairment of language comprehension, whilst speech retains natural rhythm.
List the roles of the hippocampus (subcortical region of brain), and give evidence of that.
- Found deep in the temporal lobe
- If damaged, can cause anterograde (unable to create new memories) or retrograde amnesia (generally unable to recall past memories)
Roles:
- memory formation
- memory retrieval
Evidence:
- in 1985, Clive Wearing, a composer and musician, contracted a virus that caused damage to his hippocampus, causing him memory problems.
List the roles of the corpus callosum.
Neural structures embedded deep within the cerebral hemisphere
Roles:
- connects the right and left hemispheres, allowing information to be passed between them
List the roles of the basal ganglia (subcortical region of brain), and give evidence of that.
- Large and functionally diverse set of neural structures embedded deep within the
cerebral hemispheres.
Roles:
- initiation and maintenance of movement
- balance
- posture
- Inhibit antagonist movements
Comprised of the caudate, putamen and globus pallidus.
Evidence:
- it’s associated with movement disorders such as Parkinson’s Disease and Huntingdon’s Chorea.
What two parts make up the diencephalon?
The diencephalon is a division of the forebrain situated between the cerebrum and midbrain – comprises the thalamus and hypothalamus.
List the roles of the thalamus, and give evidence of that.
Roles:
- multi modal functions
- A large collection of nuclei with various functions. Located in the dorsal part of the diencephalon.
- Relay between sensory and motor systems and the cerebral cortex.
- Regulate arousal and pain, mood, motivation, cognitive functions
Evidence:
- many different streams of information are integrated in the thalamus. Thalamus damage can results in blending of information streams, which is known as synasthesia (eg. ‘hearing’ colour, ‘feeling’ sounds) (Ro eg el., 2007)
List the roles of the hypothalamus, and give evidence of that.
Roles:
- Found above the brainstem
- a collection of small nuclei (temperature, hunger/thirst, neuroendocrine control, circadian rhythms, blood pressure/ heart rate)
- homeostatic, reproductive, and other functions (e.g fight or flight)
“Fight or flight” response involves the hypothalamus-pituitary-adrenal (HPA) axis
–> cortisol and adrenaline release
Hypothalamic dysfunction plays a role in a number of conditions:
- Hypothyroidism
- Hyperthyroidism
- Plays a key role in the body’s response to stress
What are the roles of the medulla oblongata?
What problems arise from damage to the medulla oblongata?
Homeostasis (breathing, heart rate, blood pressure) and motor movements (reflexes, fine motor movements of limbs and face in conjunction with cortex)
PROBLEMS:
If homeostasis is affected, could be stated as being ‘brainstem dead’. This is from loss of blood circulation to all brainstem regions.
If motor movements affected, could be stated as having ‘Locked-In Syndrome’. This is from loss of blood circulation to pons. Both can be caused by a stroke to the brainstem region.
Describe the spinal cord.
What injuries are associated with the spinal cord?
The spinal cord is situated within the vertebral column, with spinal nerves (part of the peripheral nervous system) communicating with the cord via notches between the vertebrae. It extends to about 45 cm. It transmits signals from/to the brain/body. It’s made up of reflexive circuits. e.g motor information from brain to body, receives sensory information from body and transmits to brain.
SPINAL CORD FUNCTIONS
-contains motor neurone that innervate skeletal muscle and allow movement
-contains motor tracts that carry information for motor movement down from brain
-receives sensory info from periphery of the body
-contains pathways where info is transmitted to the brain
SPLIT INTO TWO ROOTS
DORSAL ROOT
- Bundle of sensory neuron axons that carry sensory info into the spinal cord
VENTRAL ROOT
- Bundle of motor neuron axons that carry info away from the spinal cord towards striated muscle
There are 5 parts to the spinal cord. From top to bottom, the parts are called Cervical - at neck (7 vertebrae), Thoracic - ribs (12 vertebrae), Lumbar - lower back (5 vertebrae) , Sacral - pelvic area (5 vertebrae), and Coccygea (4 vertebrae).
INJURIES
C4 Injury: tetraplegia
C6 Injury: tetraplegia
T6 Injury: paraplegia
L1 Injury: paraplegia
TETRAPLEGIA
- Full or partial loss of sensation and movement in all 4 limbs and torso caused by damage in cervical area (C1-C5)
PARAPLEGIA
- Full or partial loss of sensation and movement in both legs (and torso- depending on location of lesion)
- Caused by damage in thoracic (T1-T12), lumbar (L1-L5) or sacral (S1-S5) areas
