Chapter 2 - Anatomy of Nervous System Flashcards
Neurons
specialized cells of the nervous system that control behaviour, the senses, and movement; ~90-100 billion; generate action potentials; release chemicals (neurotransmission)
Glial cells
structural and functional support cells for nervous system; ~50-60 billion just in cortex; do not generate action potentials
Soma (neuron structure)
contains nucleus (DNA); “sums” incoming signals
Dendrites (neuron structure)
conduct weak electrical signals towards somas (graded potentials)
Axon (neuron structure)
conduct action potentials (stronger sustained electrical signals
Axon terminal (neuron structure)
end of axons that release neurochemicals into a synapse
Synapse (neuron structure)
site of interaction between a pre and post synaptic neuron
Interneurons (functional types of neurons)
soma and axon are located in the same neural region; local circuits (nuclei)
Sensory neurons (functional types of neurons)
afferent neurons; axons project toward the CNS from sensory organs
Motor neurons (functional types of neurons)
efferent neurons; carry info away from CNS; stimulate muscles or glands
Oligodendrocytes (types of glial cells)
provide myelin sheath for some neurons; insulate and increase neural conduction
Astrocytes (types of glial cells)
part of blood brain barrier (BBB); respond to neuronal injury (gliosis); supply nutrients (NT precursors); buffer ions during neuron firing
Microglial cells (types of glial cells)
remove cellular waste; contribute to immune function within NS
Neuraxis
the axis of the neural tube front to back through spinal cord and brain; turns 90 degrees at head in bipedals
Anterior - posterior
front to back
Dorsal - ventral
top to bottom
Medial - lateral
middle to side
Coronal (cross) section
perpendicular to the anterior-posterior plane
Sagittal section
perpendicular to the medial-lateral plane
Horizontal section
perpendicular to the dorsal-ventral plane
CNS contains the ____ and the ____
brain; spinal cord
PNS refers to the ____ and contains the ____ and the ____
body; somatic NS; autonomic NS
Somatic NS
voluntary movements; body senses
Autonomic NS contains the ____ and the ____
sympathetic NS; parasympathetic NS
Autonomic NS controls….
involuntary movements necessary for life; internal organs
Sympathetic NS
prepares body for rigorous activity; fight or flight response; releases NE onto target cells
Parasympathetic NS
maintains bodily functions; rest and digest; releases ACh onto target cells
Enteric NS
regulates digestion (intestines); relatively independent
Forebrain (CNS)
cerebral cortex; large visible part of forebrain; several lobes; sub-cortical structures (ex. ganglia, limbic system, thalamus, hypothalamus
Midbrain (CNS)
superior colliculus; inferior colliculus; origin of important pathways (DA)
Hindbrain (CNS)
cerebellum; pons; medulla; locus coeruleus
Medulla (hindbrain)
regulates basic survival functions; origin of several cranial nerves (notably Vagus nerve); drugs that suppress medulla can lead to death (respiratory failure)
Pons (hindbrain)
regulates sleep; origin of several cranial nerves; important pathways for movement (connected to cerebellum)
Cerebellum (hindbrain)
coordination and timing of movements; rich in GABA (affected by alcohol)
Superior Colliculus (midbrain)
visual tracking
Inferior colliculus (midbrain)
binaural hearing
Subtantia nigra (midbrain)
origin of DA fibres projecting to forebrain; basal ganglia; important for movement
Ventral tegmental area (midbrain)
origin DA pathway to nucleus accumbens (reward centre)
Periaqueductal gray (midbrain)
regulates pain; rich in endorphins
Thalamus (forebrain)
several nuclei; relay sensory information (all except olfaction); important for consciousness
Hypothalamus (forebrain)
regulates many physiological processes (hunger, thirst, sexual desire); regulates endocrine systems (pituitary gland)
Limbic system (forebrain)
group of subcortical forebrain structures involved in regulating emotional behaviour (amygdala, hippocampus, cingulate gyrus)
Basal ganglia (forebrain)
important for movement (habits)
Nucleus accumbens
near basal ganglia; reward centre; strongly activated by addictive (highly rewarding) drugs; dopamine release (from VTA)
Cerebral cortex
is convoluted (gyri/bumps and sulci/fissures); contains four major lobes
What are the 4 major lobes in the cerebral cortex?
occipital, temporal, parietal, frontal
Occipital lobe (cerebral cortex)
processes visual info
Temporal lobe (cerebral cortex)
auditory processing and language functions; visual processing (shapes)
Parietal lobe (cerebral cortex)
includes somatosensory cortex that processes touch related info from body; vision (movement); taste
Frontal lobe (cerebral cortex)
includes primary motor cortex which controls voluntary movement (incl lang prod); important for attention, short-term memory, decision making (executive functions); regulates emotion; olfaction
Prefrontal cortex (controlling voluntary movement)
signals that movement should occur
Motor cortex (controlling voluntary movement)
receives motor info from prefrontal cortex and sends it to spinal cord
Basal ganglia (controlling voluntary movement)
involved in stabilizing movements and habits (“automatic” behaviours)
Cerebellum (controlling voluntary movement)
maintains sequence and timing of movements
What is cerebrospinal fluid?
clear fluid produced by cells in brain; fills space between meninges; provides cushioning; pathway for nutritional support, hormones, and metabolites
Genes
segment of DNA that codes for a specific trait within an organism
Polymorphisms
differences in gene sequences that result in differences in protein expression; can effect how long a drug remains in body or potency of a drug (liver enzymes, receptor number)
Transcription
expression of DNA into RNA
Transcription factor
substance that increases or decreases transcription
Epigenetics/neurogenetics
study of gene expressions that do not involve alterations in the DNA sequence (ex. alcohol expression can increase gene expression even in offspring)
CRISPR
way of editing genes or turning them off altogether; has been used to treat sickle disease
