Chapter 2 - Brain Anatomy and Physiology Flashcards
the brain is plastic
nerve tissue can adapt to the world by changing how its functions are organized
neuroplasticity
the ability of the nervous system to undergo a physical or chemical change that improves its adaptability to environmental changes and the ability to compensate for damage (learning)
phenotypic plasticity
the ability of an individual to develop into more than one phenotype
primary function of the brain
produce behavior
- requiring perception
- integration of information
- action
central nervous system (CNS)
- consists of the brain and spinal cord
- underlies complex behavior
peripheral nervous system (PNS)
- consists of everything apart from the brain and spinal cord
- brings sensory information to the CNS and brings motor instructions from the CNS to the muscles in the body
somatic nervous system (SNS)
- a part of the PNS
- contains all spinal and cranial nerves that transmit sensory information to the CNS from the muscles, joints, and skin
- transmits outgoing motor instructions that move
- neurons within the somatic department of the PNS connect through the brain and spinal nerves to the receptors on the surface of the body and muscles
- under the influence of will
autonomic nervous system (ANS)
- a part of the PNS
- balances internal organs by producing the rest-and-digest response by the parasympathetic (calming) nerves or the fight-or-flight response by the sympathetic (awakening) nerves
- not under the influence of will
flow of neural information of the CNS
- afferent (incoming) information is sensory and enters the CNS or one of its components
- efferent (outgoing) information leaves the CNS or one of its components
dorsal (brain-body orientation)
structures located at the top of the brain
ventral (brain-body orientation)
structures located at the bottom of the brain
anterior (brain-body orientation)
structures at the front of the brain
posterior (brain-body orientation)
structures at the back of the brain
medial (brain-body orientation)
structures located towards the center of the brain
lateral (brain-body orientation)
structures located towards the sides of the brain
rostral (spatial orientation)
beak
posterior or caudal (spatial orientation)
tail
superior or dorsal (spatial orientation)
back
inferior or ventral (spatial orientation)
belly
coronal section
vertical cut, from the crown to the bottom (seen from the front)
horizontal section
horizontal cut (seen from above)
sagittal section
longitudinal cut from the front to the back (seen from the side)
ipsilateral
structures that lie on the same side of the body
contralateral
structures that lie on opposide sides
bilateral
structures are in both hemispheres
proximal
structures close together
distal
structures far apart
meninges
the first structure (made up of 3 layers) visible when the skull is cut open, protecting the brain
- dura mater
- arachnoid membrane
- pia mater
- leptominges
dura mater
- “hard mother”
- the outer layer is a strong double layer that provides protection
arachnoid membrane
- “cobweb”
- the thin middle layer, it is called the cobweb because of its fine threads that are attached
pia mater
- “soft mother”
- the inner layer that clings to the brain surface and provides protection
leptominges
- “leptos” = thin
- arachnoid membrane + pia mater
cerebrospinal fluid (CSF)
flows between the pia mater and the arachnoid membrane
- serves as a cushion for the brain so that it can move or expand slightly without pressing on the skull
- also flows in the spinal cord, which is also wrapped in the meninges
- brings nutrients to the brain and removes waste
meningitis
inflammation of the meninges
encephalitis
inflammation of the brain
frontal lobe
specialized in executive brain functions such as decision making
temporal lobe
has functions related to hearing, language, musical abilities, and emotional processing
parietal lobe
specializes in directing our movements towards a goal or performing a task, such as grabbing an object
occipital lobe
specializes in visual processes
gyri and sulci
gyri - the bumps of the cerebral cortex
sulci - the grooves on the cerebral cortex
fissures
deeper grooves of the cerebral cortex
cerebrovascular accident (CVA)
- stroke
when there is a sudden appearance of neurological symptoms because of severely interrupted blood flow in the brain
ischemic stroke
when a blood vessel is blocked by a clot
- less severe becasue only a localized region is affected
haemorrhagic stroke
when a blood vessel bursts and blood flows into the brain
- very severe
grey matter
consists of nerve cell bodies, in which neurons collect and modify information
- on the outside of the brain
white matter
consists of nerve fibers, which are wrapped in an insulating layer and are responisble for longer-distance connections between neurons
- on the inside of the brain
ventricles
4 cavities in the brain in which CSF is located
corpus callosum
connects the 2 hemispheres and ensures communication between the 2 halves
main cells
- neurons: perform the highest functions of the brain
- glial cells: help and regulate the activities of neurons
axons
fibers connecting neurons
- when they run along each other in a bundle, they form what is called a nerve outside the CNS, or a tract inside the CNS
spinal cord
- carries signals to the muscles for movement to occur
- feeds information to the brain
- grey matter is on the inside
- white matter is on the outside
brainstem
- starts where the spine enters the skull
- receives afferent nerves from all of the body’s senses and directs efferent nerves from the brain to the spinal cord to control movements (except fingers/toes)
- responsible for most unconscious behavior and can be divided into: hindbrain (myelencephalon and metencephalon), midbrain (mesencephalon), and between brain (diencephalon)
hindbrain (meyelencephalon and metencephalon)
- controls motor functions from breathing to fine movements such as dancing
- contains the cerebellum
- contains the reticular formation, the pons, and the medulla
cerebellum
controls complex, finely coordinated movements, such as dancing and running
reticular formation
contains a mixture of neuron cells and nerve fibres
- has to do with the sleep-wake rhythm and arousal
the pons
- contains substructures that control many important movements of the body
- forms a bridge from the cerebellum to the rest of the brain
the medulla
responsible for vital functions such as breathing and the cardiovascular system
metencephalon
made up of pons and cerebellum
myencephalon
the medulla
midbrain (mesencephalon)
made up of:
- tectum
- tegmentum
tectum
- the sensory component
- lies dorsally/posterior
made up of: - superior colliculus: receives visual information
- inferior colliculus: receives auditory information
function of the colliculi
process sensory information and produce orienting movements
- such as turning your head to see where sound is coming from
tegmentum
- lies ventrally/anterior
- consists of many nuclei that often have movement-related functions
red nucelus
control the movements of the limbs
substantia nigra
responsible for initiating movement
- connected to the forebrain
degeneration of substantia nigra
associated with Parkinson’s disease
periaqueductal grey matter (PAG)
consists of cellular bodies that surround the water pipes of the third and fourth ventricles
- responisble for species-specific behaviors
between brain (diencephalon)
- integrates sensory and motor information on its way to the cerebral cortex
- consists of the thalamus and the hypothalamus
thalamus
- a gateway for channelling sensory information to the cerebral cortex from all senses
- allows you to focus on one conversation in a room full of people
hypothalamus
- controls hormone production through its interaction with the pituitary gland
- important in almost all aspects of behavior, hormone function, sleep, temperature, nutrition, and sexual and emotional behavior
forebrain
- cerebral cortex
- basal ganglia
cerebral cortex
regulates mental activities such as perception, planning, emotions, and memory
allocortex
- plays a role in the control of motivational and emotional states, certain forms of memory
- includes the structures: hippocampus (involved in memory consolidation), amygdala (linked to emotions, particularly fear), cingulate cortex (important in learning and motivation)
neocortex
- constructs a perceptual world and responds to it
basal ganglia
controls voluntary movements
- consists of the caudate nucleus, the putamen, and the globus pallidus
hypoactivity and hyperactivity
too little and too much dopamine
- hypoactivity causes Parkinson’s
- hyperactivity causes Tourettes
the limbic system
a collection of brain structures that regulate emotional and sexual behavior, memory, and motivation
- includes the hippocampus and the amygdala
olfactory system
- includes the olfactory bulbs at the front of the brain that are responsible for our sense of smell
cranial nerves
- have afferent functions such as sensory input to the brain from the eyes, ears, mouth, and nose
- can have efferent function such as the motor control of muscles in the face
- 12 pairs of cranial nerves
the 12 cranial nerves and functions
Bell’s Palsy
- caused by the inflammation of the facial nerve (7th cranial nerve)
- leads to swelling and compression, resulting in a partial loss of nerve function
spinal nerves
obtain information from sensory receptors from the rest of the body and the PNS
lie on the left and right sides of the spinal cord (bilateral parts) and are protected by vertebrae, divided into 5 sections from top to bottom:
- cervical
- thoracic
- lumbar
- sacral
- coccygeal
dermatome
each segment of the body
- has 2 spinal nerves each:
- a sensory (afferent) nerve and a motor (efferent) nerve
Bell’s and Magendie’s law
the posterior/dorsal spinal cord is sensory, and the anterior/ventral spinal cord is motor
- dorsal root is sensory (afferent), perceives pain, temperature, and touch
- ventral root is motor (efferent), is responsible for muscle movement and reflexes
sympathetic division of the ANS
- stimulates the body by activation and arousal (fight or flight)
- connected to the thoracic and lumbar spinal cord segments
- ganglia are near the spinal cord with short preganglionic (acetylcholine neurotransmitters) and long postganglionic (norepinephrine neurotransmitters) fibres
parasympathetic division of the ANS
- inhibits the body by relaxation and digestion (rest and digest)
- connected to sacral spinal cord segments, but mostly to 3 cranial nerves (vagus, facial, and oculomotor)
- ganglia are near target organs with long preganglionic (acetylcholine) and short postganglionic (acetylcholine) fibres
