Lecture 5: Brain Anatomy l Flashcards
anterior
in front
posterior
behind
superior
above
inferior
below
rostral
towards the beak
caudal
towards the tail
dorsal
towards the back
ventral
towards the belly
neuraxis
an imaginary line that runs along the length of the CNS
lateral
away from the midline
medial
towards the midline
sagittal plane
cuts the brain in half between the eyes
horizontal plane
cuts the brain into its superior and inferior portions
transverse plane
cuts the brain into its front and back portions
contralateral
structures on opposite sides of the body
ipsilateral
structures on the same side of the body
what systems are ipsilateral
taste and smell
what sensory systems are contralateral
everything except taste and smell
superficial
located close to the surface
deep
located far away from the surface, deep in the interior of the animal
proximal
nearby
distal
far away
brain nuclei
a collection of neurons that are clustered together and all work together to serve some functions
blood-brain barrier
a semipermeable barrier between the blood and brain. the blood capillaries that pass through the brain and spinal cord do not have gaps in them.
what would happen if blue dye was injected into an animal’s bloodstream?
all tissues except the brain and spinal cord will be tinted blue
how does the brain generate extracellular fluid in the CNS?
the brain generates extracellular fluid by picking out what it needs from the blood and making a solution called cerebrospinal fluid (CSF)
cerebrospinal fluid (CSF)
extracellular fluid in the CNS made from choroid plexus (a tissue found in each brain ventricle)
how is extracellular fluid generated in the PNS?
the lymphatic system
the lymphatic system
produces extracellular fluid in the PNS. blood vessels have small holes that leak out plasma. the plasma then becomes lymph which is the extracellular fluid. it floats around to cells providing nutrients and collecting waste. then, lymph is collected in lymph vessels and brought into lymph nodes which detect and destroy any invading organisms or foreign particles and then they return the lymph to the blood to start the process again.
meninges
the 3 tough, protective tissues that surround the brain
dura matter
outer layer of thick tough and unstretchable tissue
arachnoid matter
the middle layer of soft and spongy tissue with a web-like appearance
pia matter
inner layer
subarachnoid space
the area between the arachnoid mater and the pia matter. filled with CSF
what are ventricles
interconnected hollow spaces in the brain
how many ventricles are there
4
1st and 2nd lateral ventricles
large ventricles that sit underneath the cerebrum
3rd ventricle
lies between the two thalamic nuclei
4th ventricle
sits between the pons and the cerebellum
cerebral aqueduct
a long, tube-like structure that connects the third and fourth ventricles
where is CSF found
in the ventricles and flows throughout the brain and spinal cord before it is absorbed into the blood supply
when is CSF made
continuously
how often is CSF replaced?
half replaced every 3 hours
main parts of the nervous system
CNS & PNS
central nervous system (CNS)
everything in the brain and spinal cord
types of neurons in the CNS
interneurons and projection neurons
how is the myelin in the CNS created
oligodendrocytes
interneurons
CNS neurons whose axons stay local (only make synapses on nearby neurons)
projection neurons
CNS neurons whose axons go outside the area where the soma is located
peripheral nervous system (PNS)
any part of the nervous system outside the brain and spinal cord
how is the myelin in the PNS created
Schwann cells
types of neurons in the PNS
motor neurons and sensory neurons
motor neurons
control muscle contraction and gland secretion and send information away from the CNS
sensory neurons
detect changes in the external and internal environment and send information to the CNS
spinal nerves
attach to the spinal cord to allow it to communicate with the rest of the body
cranial nerves
attach to the brain to allow it to communicate with the rest of the body
how many pairs of spinal nerves are there?
31
how many pairs of cranial nerves are there?
12
the function of the spinal cord
distribute motor fibres to the effector organs of the body and collect somatosensory information to be passed on to the brain
t or f: the spinal cord has autonomy from the brain
true, various reflexive control circuits are located there
2 main components of the PNS
somatic and autonomic nervous systems
somatic nervous system
interacts with the external environment
autonomic nervous system
regulates the body’s internal environment
somatic afferent signalling
carries sensory signals to the CNS
somatic efferent signalling
carries motor signals from the CNS to skeletal muscles
autonomic afferent signalling
carries sensory signals from internal organs to the CNS
autonomic efferent signalling
carries motor signals from the CNS to internal organs
2 parts of the autonomic nervous system
sympathetic and parasympathetic divisions
sympathetic division
primes the body for action, particularly in life-threatening situations (fight or fight)
parasympathetic division
supports activities that occur when the body is in a relaxed state and all is well “rest and digest”
3 major divisions of the brain
forebrain, midbrain, hindbrain
hindbrain
includes the medulla, pons, and cerebellum
medulla
regulates different autonomous (involuntary) functions such as heart rate, blood flow, and sneezing. the blood-brain barrier is noticeably weaker here
pons
large bulge connected that relays information between the cerebrum and the cerebellum. contains cranial nerve nuclei which participate in hearing, balance, taste, and sensations in the face.
cerebellum (little brain)
plays an important role in motor control. doesn’t initiate movement but contributes to coordination, precision, and accurate timing
what ventricle is the pons found in
4th
what ventricle is the cerebellum found in
4th
the glymphatic system
in the CNS the brain generates CSF by picking out what it needs from the blood
chloroid plexus
tissue in all ventricles. site of CSF production
site of CSF fluid production
choroid plexus
lymphatic system is used in the
PNS
glymphatic system is used in the
CNS
affrent signalling
signals being sent in
efferent signallign
signals being sent out
