NSCI 200: L3 - Brain Anatomy

dorsal

toward the back for body, top of brain for 4-legged animals

ventral

toward the stomach

anterior

toward the front end

anterior

toward the front end

superior

above another part

inferior

below another part

lateral

toward the side, away from the midline

medial

toward the midline, away from the side

proximal

located close (approximate) to the point of origin or attachment

distal

located more distant from the point of origin or attachment

ipsilateral

on the same side of the body (e.g., two parts on the left side)

contralateral

on the opposite side of the body (e.g., one on left and other on right)

rostral

toward the front of the head, toward the nose

caudal

toward the back end, toward the tail end

grey matter

composed mainly of neuron cell bodies + dendrites + glial cells, typically organized into layers, processes information and handles thinking

parasagittal plane

divides the body into right and left sides

longitudinal section

a section that is parallel to the midline of the body (vertical)

coronal plane (brain)

divides the brain into anterior and posterior sides

horizontal plane (brain)

divides the brain into superior and inferior parts

central nervous system (CNS)

contains the brain and spinal cord

peripheral nervous system (PNS)

nerves and ganglia located outside the CNS

autonomic nervous system

regulates involuntary processes (e.g., heart rate, blood pressure, secretion of saliva, etc.)

parasympathetic and sympathetic nervous systems

act on many of the same organs with opposite effects (e.g. parasympathetic increases heart rate, sympathetic decreases)

enteric nervous system

located mainly within the the walls of the intestines, regulates many processes of digestion

somatic nervous system

controls voluntary skeletal muscles and transmits sensory information to the CNS

motor (somatic NS)

motor neurons taking signals from CNS out into the body (typically muscles for movement)

sensory (somatic NS)

sensory neurons taking sensory signals from the periphery to the CNS

What are the 2 branches of the PNS?

autonomic NS and somatic NS

What are the 3 branches of the autonomic NS?

parasympathetic NS, sympathetic NS, enteric NS

What are the 2 branches of the somatic NS?

motor and sensory

ganglia

a cluster of neuron cell bodies located in the PNS

nuclei

a cluster of neuron cell bodies located in the CNS

tracts/fiber tracts/projections

a bundle of axons within the CNS

nerve

a bundle of axons within the PNS

white matter

mainly composed of myelinated axons + glial cells, helps with communication between grey matter areas and the rest of the body

grey matter

composed mainly of neuron cell bodies + dendrites + glial cells, typically organized into layers, processes and transmits information + controls movement + memory + emotions

ventricles

4 interconnected cavities within the brain filled with cerebrospinal fluid (CSF)

meninges

3 membranes that surround the brain and spinal cord

dura mater

tough, durable outer layer

arachnoid mater

a thin membrane in between the dura and pia maters

pia mater

innermost membrane that adheres tightly to the surface of the brain

no

Does the brain have pain receptors?

yes

Do meninges have pain receptors?

meningitis

inflammation of the meninges, often caused by a bacterial or viral infection that is painful and can be fatal if not treated properly

forebrain

yellow and orange portion (____brain)

midbrain

pink portion (____brain)

hindbrain

purple portion (____brain)

telencephalon

yellow part

diencephalon

orange part

mesencephalon

pink part

rhombencephalon

purple part

medulla

lower dark blue part

pons

upper dark blue part

cerebellum

teal part

cerebral cortex, hippocampus, amygdala, basal ganglia, olfactory bulb, basal forebrain

What are some major structures included in the telencephalon?

thalamus, hypothalamus, posterior pituitary gland, pineal gland

What are some major structures included in the diencephalon?

tectum, tegmentum

What are some major structures included in the mesencephalon?

superior colliculus, inferior colliculus

What are some major structures included in the tectum?

substantia nigra, cerebral peduncle, ventral tegmental area

What are some major structures included in the tegmentum?

medulla

responsible for regulating many involuntary processes (e.g., breathing, heartbeat frequency, blood pressure, vomiting, cough reflex), receives input about proprioception (position of body) and muscle tension → relays it to cerebellum

medulla and pons

What part of the brain contains nuclei for several cranial nerves?

cranial nerves

a nerve that emerges directly from the brain

afferent, efferent, mixed

What are the 3 types of cranial nerves?

afferent nerves

conduct sensory signals from sensory structures to the CNS

efferent nerves

conduct signals from CNS to target tissues (e.g., muscles, glands)

mixed nerves

contain some afferent axons and some efferent axons

pons

regulating breathing and sleep/wake cycle, contains the locus coeruleus

locus coeruleus (LC)

a nucleus which produces norepinephrine and plays an important role in mental arousal (alert/wakeful) + attention/memory + stress response

mammals

Only _______ have distinct pons

pons

many fibre tracts pass through the ______ — axons from each half of the brain decussate (cross) to the opposite side of the spinal cord such that the left hemisphere controls the muscles of the right side of the body and vice versa

cerebellum

extensively folded with outer cerebellar cortex of grey matter surrounding white matter, helps regulate motor movement + balance + coordination, important for shifting attention between auditory and visual stimuli, critical for certain types of learning (e.g. forming procedural memories)

Purkinje cell

large, distinctive neurons located in the cerebellar cortex of the brain

cerebellar cortex

the outer layer of gray matter that covers the cerebellum

1 Purkinje cell can have _________ synapses with parallel fibres of granule cells

7 million

granule cells

a class of very small neurons that make up the most numerous type of neuron in the human brain

reticular formation

red part (extends through the medulla, pons, and midbrain)

reticular formation

regulates sleep/wake cycles, circadian rhythms, coordinates heart rate + blood pressure + respiration, motor coordination (stabilizes posture during voluntary movement)

raphe nuclei

part of the reticular formation that produces serotonin → affects mood, emotions, perception of pain

tectum, tegmentum

What are the two major structures that the midbrain is divided into?

dorsal

Is the tectum the dorsal or ventral region of the midbrain?

ventral

Is the tectum the dorsal or tegmentum region of the midbrain?

tectum

purple part

tegmentum

pink part

tectum

the “roof“ of the midbrain that contains the superior colliculus and inferior colliculus

superior colliculus

upper part of tectum

inferior colliculus

lower part of tectum

superior colliculus

processes and integrates visual + auditory + somatosensory information, using it to coordinate head and eye movements for gaze shifts

inferior colliculus

processes and integrates input from auditory and somatosensory systems to determine the location of sounds, may help filter sounds and initiate wakefulness in response to certain sounds

tegmentum

contains the rostral region of the reticular formation, the nuclei for 2 cranial nerves, the cerebral peduncle, substantia nigra, and ventral tegmental area

cerebral peduncle (crus cerebri)

dark green part

cerebral peduncle

a region of white matter fibre tracts: output from the cerebrum to the pons, medulla, and spinal cord

substantia nigra

black parts

contains a high concentration of pigment neuromelanin

Why does the substantia nigra look dark

cerebral peduncle, substantia nigra, ventral tegmental area

What are the 3 major parts of the tegmentum?

substantia nigra

produces dopamine, outputs to the basal ganglia contribute to regulation of initiation of voluntary movement, involved in spatial learning and reward processing

ventral tegmental area (VTA)

blue part

ventral tegmental area

contains many neurons that produce dopamine, controls reward processing + motivation + learning + memory, involved in addition behaviours

cerebral aqueduct

green part

cerebral aqueduct

small canal-like structure between tectum and tegmentum that cerebral spinal fluid can flow through, connects the fourth ventricle to the third ventricle