Lecture 6 Flashcards
CNS
everything in brain and spine
Interneurons are CNS neurons whos axon stays local
Projection neuron is a CNS or PNS neuron with an axon that goes far
PNS
All parts outside the brain and spinal chord
The axons of motor neurons
Which are efferent fibers from the CNS
Controlling muscles and glands
Sensory neurons
Afferent fibers info towards the CNS
These detect changes in the internal and external environments
Peripheral nervous system
CNS communicates with the rest of the body via the 31 pairs of spinal nerves
12 pairs of cranial nerves
Spinal chord
Long, conical structure.
Distributes motor fibers to effector organs and collects somatosensory information
Reflexes are also here
White matter
Axons (myelinated)
Dark matter
Cell bodies
Somatic PNS
Interacts with the internal environment
Afferent and efferent
Autonomic
sensation and regulation of smooth muscle. The ANS interacts with the bodies internal environment
Sympathetic
Fight/flight
always active to some extent as it regulates heart rate, blood flow and the activity of body organs. When acutely stimulated, blood goes from organs to muscles to increase survival
Parasympathetic
Rest digest, feed, breed
Increasing bodies energy stores (digestion)
Hindbrain components
Cerebellum, pons & midbrain
Many cranial nerves come out of the pons and medulla
The primary crossing of descending motor neurons is in the hindbrain
Medulla oblongata
Most caudal part of the brain stem. Collection of nuclei that regulate much autonomic functions such as heart rate that are autonomic and essential for life.
The area postreama has a pourus blood brain barrier and detects chemicals in blood. Can vomit.
Also contains part of the reticular formation which facilitates alertness and sleep.
Pons
Relays info from cerebrum and cerebellum.
Also has part of the reticular formation - sleep
Also has cranial nerves, hearing, balance, taste and sensations on the face
Cerebellum
Motor control
Tightly folded surface
Doesn’t initiate movement but makes it more coordinated and precise
Integrates sensory and motor information to exert a coordinating and smoothing effect on movement and cognition. Plays a role in motor learning especially when parts of the body grow and change (so necessitate adjustments in motor patterning)
Cerebellar damage = jerky movements. Excessive = cannot stand.
Midbrain
Regulates aspects of hearing, vision, motivation, movement and arousal. 2 bits
Tectum
Is the roof of the midbrain
Is 2 bumps on the dorsal surface of the midbrain
Top bumps are the superior colliculi - orientating toward a visual stimulus
Inferior colliculi - orientating towards an audio stimuli
Important for recognizing danger,
Tegmentum
Rostral reticular formation (sleep and arousal)
Periaqueductal gray - species specific responses to pain (like running away or threatening posture)
Substancia nigra (motivation and regulation of purposeful movement (Parkinson’s)
Copy & Paste forebrain
Does what the hindbrain does but via hormones instead of axons
Hypothalamus
Bilateral, several nuclei which regulate hormonal systems
4 Fs, feeding, fighting, fleeing and mating
Different nuclei control temp, sleep/wake, hunger, social behaviour
Links CNS to endocrine system
Thalamus
Relays sensory information to cerebellum
Also sleep/wake cycle
Lateral geniculate nucleus takes info from eye and sends it to the primary visual cortex
Medial geniculate cortex covers audio information
Basal ganglia
Collection of nuclei
Regulates movement and does reinforcement learning and habit
Many neurological disorders are caused by damage here
The limbic system
Cingulate cortex is a large area over the corpus callosum, Means encircling. Connects many parts of the limbic system
Hippocampus and amygdala are located in the temporal lobe of the cerebral cortex
Hippocampus - explicit memory formation
Amygdala - feeling and recognizing emotions eg fear
Fornix is a fiber bundle that carries signals between the septum/mammillary bodies (means arc)
The septum passes info too and from the hippocampus and amygdala
The mammillary bodies (part of the hypothalamus) are connected to the hippocampus and amygdala and are important for memories
Cerebral cortex
6 layered structure (3 in birds and lizards). Neurons are connected such that they create columns, partially distinct functional units.
Largest site of neural integration. Attention, perception, thought, memory, language decision making and consciousness.
Sulci
fissures
gyri
Small grooves (important is the central sulcus, separating the rostral and caudal divisions of the hemispheres
large grooves - longitudinal, lateral (frontal from temporal)
ridges between sulci or fissures
frontal lobe
movement from primary motor cortex and planned movement via the premotor cortex
parietal lobe
touch via somatosensory cortex
occipital lobe
primary visual cortex
temporal lobe
primary audio cortex
Seonsory association cotec
Each primary sensory area has one
Perception takes place here and memory is stored there
If you had damage to the primary audio cortex and the auditory association cortex, not only could you not hear a dog barking but you could not even remember what a dog barking sounds like. Could still orientate yourself to a sound or a sight but could not perceive it. Cortical blindness/deafness.
