Ch.2, Nervous System Anatomy Flashcards
Agenesis of the cerebellum symptoms, cognitive and motor; symptoms if it occurs in childhood
Failure of brain region to develop
Cerebellum contains 80% of the neurons in the human brain
Cerebellum does have higher cognitive functions which is unique for a lower brain region
Ataxia: failure of motor coordination: ataxia, distinctive speaking pattern, awkward gait, and difficulties with balance
Cognitive Difficulties: difficulty planning, abstract thinking, and language
Some of this agenesis did get better due to brain plasticity, in this case other structures likely helped out
If this occurs as a child, severe visuomotor deformities
Agenesis: failure of brain region to develop, very rare
Always functional connectivity: structures never operate independently
Sensory input function of the nervous system
conduction of signals from sensory receptors to the CNS, all info coming into brain via the peripheral nervous system; sensory neurons carry info into the CNS
Sensory neurons vs receptors
Sensory Neurons can act as both a receptor and carrying info
USUALLY Rods and cones (receptors) synapse with neurons
CNS, (2) Integration
analysis and interpretation of the sensory signals and formulation of responses
OCCURS ONLY IN CNS, ALWAYS ARE WITHIN CNS ALL THE TIME spinal cord or brain
Interneurons carry out this function: usually means between, cells that exist in circuits with other neurons, but they are always in between
ALWAYS IN THE MIDDLE
Motor Output, functions of the CNS
Not just motor output, can be output into organs
Coming out of CNS, going to periphery, to send to effector cells (like muscle cells, organs, glands)
Dendrites and cell bodies are in the CNS: AXONS AND AXON TERMINALS LEAVE THE CNS IN ORDER TO SYNAPSE WITH EFFECTOR CELLS
Transduce/transduction:
one form of stimuli and converting it to another (stretch receptor: mechanical energy–converting it into chemical energy)
Perception:
making sense of sensations and creating your subjective reality: NO ONE’S PERCEPTION IS THE SAME
principle 9 of nervous system organization
The nervous system produces movement in a perceptual world that it constructs
Sensory organs convert info about the world (sensory stimuli) into biology activity; cellular and chemical processes that constructs perceptions = subjective reality
One reality is not better than the other, they are just different
Adaptations over time equip each species with a view of the world that enhances their reproductive success
principle 10 of nervous system
Brain Is plastic
Neural tissue has the capacity to change in response to the world by modifying its organization
The more complex the brain = the more plastic it is
For example, the congenital blindness may result in increased higher
Organization of nervous system
Central Nervous system: brain, spinal cord, retina
Peripheral Nervous System: somatic nervous system and autonomic nervous system, enteric nervous system
CNS: mediates behavior
SNS: transmits sensation FROM ALL SENSES, produces movement, cranial nerves, and spinal nerves, conscious (effector cells = skeletal muscles) muscles joints and skin
ANS: sympathetic division, parasympathetic division, unconscious, homeostasis, urination, heart rate, etc.
PART OF ANS, Sympathetic: fight or flight, arousal (effectors=organs and glands)
PART OF ANS, PSNS: opposite, calming, brings it to baseline, rest and digest (effectors=organs and glands)
Dorsal/Superior, ventral/inferior, medial, lateral, anterior, posterior,
Dorsal/superior: up
Ventral/inferior; toward the floor
Medial: toward midline
Lateral: toward side
Anterior: front of face out
Posterior: back out
Coronal section, horizontal section, saggital section
Coronal Section/ gives frontal view cut from vertical, get dorsal vs ventral and medial vs later, CANNOT GET ANTERIOR AND POSTERIOR
Horizontal Section Dorsal View: gNO DORSAL VS VENTRAL, can see anterior, posterior, medial, and lateral
Medial view/Saggital Section: typically looking at right hemisphere, dorsal, ventral, anterior, posterior BUT NO LATERAL OR MEDIAL
Epsilateral vs contralateral
“EPSI” SAME SAME
“Contra” opposite side
Bilateral representation
Hippocampus is bilateral: has a left and a right
3 layers protecting the nervous system/brain (meninges)
(1) Durameter: hard mother, toughest layer
(2) Arachnoid membrane: mainly connective tissue, looks like a spiderweb
Subarachnoid Space: between arachnoid and pia mater, filled with cerebrospinal fluid
(3) Pia Mater: soft mother but still moderately tough, follows all the brains contours
Symptoms and etiology of meningitis
Any type of infection can cause
Meninges get inflamed and press on brain
Symptoms: severe headache, stiff neck/head retraction, convulsion (last symptom only happens if brain starts to get damaged)
Treatment: antibiotics if bacterial
May result in long term consequences like deafness, epilepsy, cognitive deficits
Pitekia rash: burst blood vessels looks like purple dots
Encephalitis: infection of the brain itself; different forms have different effects on the brain
Rasmussen Encephalitis
attacks one cerebral hemisphere and requires a hemispherectomy (no known cause, shares some features of autoimmune disorders)
Allocortex
Allocortex: evolutionarily older, made of hippocampus and amygdala
Indentations vs bumps and ridges in the brain
Indentations in the brain: sulci (singular = sulci)
Bumps and ridges: gyri (gyrus, singular)
Central sulcus
divides frontal lobe from parietal
Lateral Fissure/Sylvian Fissure: f
forms the border of the temporal lobe
S1:
in parietal lobe,primary somatosensory cortex = postcentral gyrus
M1:
primary motor cortex, precentral gyrus, movements of individual muscles, frontal lobe
Pyramidal cell
tear drop shape/triangular, predominant cell types of the cortex / primarily interneurons in the cortex
Astrocyte:
star shaped, glial cell
Gray matter:
outside, neocortex, made up of cell bodies, dendrites, and capillaries (pinkish grey bc of capillaries)
Oligodendrocyte vs schwann cell
Oligodendrocyte: responsible for myelination in CNS
PNS: schwann cell responsible for myelination in the PNS
Node of Ranvier
The nodes of Ranvier are the only sites along a myelinated nerve fiber that support the fast de- and repolarization process necessary for generation of action potentials.449
Difference between nuclei and ganglia
Nuclei plural, nucleus single: IN CNS, tend to be buried pretty deep
Ganglia plura, ganglion plural: IN PNS
Tracts vs nerves
Tracts: large collection of axons coursing together IN THE CNS
Nerves: OUTSIDE THE CNS ^^ fiber pathways carrying info from one point to another
Location of the 4 ventricles
2 lateral ventricles: right and left, one in each hemisphere
3rd ventricle, in part of the brain stem
Fourth ventricle: base-most part of the hindbrain
Cerebral aqueduct
Cerebral Aqueduct: canal that connects third and fourth ventricles, and sends cerebrospinal fluid down the spine
Bidirectional flow of info in the brainstem
can flow bottom-up: spinal cord to cerebrum
can flow top-down: cerebrum downward
Brainstem
evolutionarily oldest
begins where spinal cord enters skull
RECEIVES AFFERANT SIGNALS from the body’s senses; then sends efferent signals out to the spinal cord to control most of the body’s movements
3 parts of the brain stem
Reticular formation: netlike mixture of nuclei and fiber pathways; nuclei are located in patches along its length: SLEEP WAKE BEHAVIOR, STIMULATES THE CEREBRUM, if damaged = coma
Pons: bridge between cerebellum and brain, vital body movements, breathing, relay between CEREBELLUM And brain
Medulla: cardiovascular system, breathing, relay between brain and spinal cord
Cerebellum functions
movement timing and precision, motor learning, balance, posture, increases in size with the speed and dexterity of the species
Midbrain, tectum and tegmenjtum
Tectum (roof): dorsal in humans, sensory structure, posterior, produces orienting movements (toward sound or other stimulus)
Tegmentum (floor); anterior in humans, ventral, species specific behaviors, perceptions of pain
Three components of the diencephalon and functions
-thalamus: takes in info, sends it to the cerebrum, relay station, all sensory info is organized and integrated here
-Pituatary gland: master gland, hormone release
Hypothalamus: regulates hormone release from pituitary, sexual behavior, temperature regulation, eating, drinking
Thalamus: Medial geniculate nucleus and lateral geniculate nucleus
The medial geniculate nucleus (MGN) and lateral geniculate nucleus (LGN) are the specific thalamic nuclei that relay the auditory and optic pathways, respectively
3 parts of the forebrain
cerebral cortex, basal ganglia, olfactory bulbs
Two parts of the cerebral cortex
neocortex: perception, planning, emotions, memory
allocortex: role in emotional and motivational states
Two parts of the basal ganglia in forebrain
coordination of voluntary movements; collection of nuclei below the white matter of the cortex = made up of caudate nuclei and putamen
Hippocampus
memory consolidation, crystallization, specifically autobiographical and episodic; one of the earliest and most severely affected structure in many disorders like Alzheimers
Motor Cortex Layers
I, I, III: integrative functions
IV: sensory input, afferent
V: output to other parts of the brain (efferent), much larger in motor cortex
VI: output to other parts of the brain, much larger in motor cortex
Striatem
includes the caudate nucleus and putamen
Globus pallidus
). The primary function of the globus pallidus is to control conscious and proprioceptive movements.
Organization of the somatic nervous system nerves from head down (4)
Cervical nerves
Thoracic nerves
Lumbar nerves
Sacral nerves
Law of Bell and Magendie
structures that are posterior = almost always sensory
structure that are anterior= almost always motor
Watermelon analogy of the forebrain/neocrotex
Extending our analogy between the brainstem and your forearm, imagine that the fist (the diencephalon) is thrust inside a watermelon — the forebrain, with the neocortex as the rind and the allocortex and basal ganglia as the fruit inside. Just as watermelons come in various sizes, so do brains, which in a sense is what evolution has done: the forebrain varies considerably in size across species.
what is the neocortex composed of?
6 layers of grey matter that sit on the corpus collosum, which joins the two hemispheres
dorsal vs ventral; streams
dorsal stream is unconscious, it is the where
ventral stream is concious, it is the what
