Lecture 7 - Brain anatomy

Name and define the 2 parts of the nervous system

• CNS - brain/spinal cord

• PNS - nervous system outside of brain/spinal cord

define oligodendrocytes, where are they found

type of glial cell, CNS

define the function of schwann cells and where they can be found

create myelin, PNS

how many myelin sheaths are created by each schwann cells

one

if blue dye is injected into the bloodstream, which parts of the body will not be tinted blue

brain and spinal cord

what is the main difference between capillaries in the brain/spinal cord as opposed to the rest of the body

in the body, capillaries have gaps allowing substances to flow in and out of the bloodstream, these gaps do not exist in the capillaries in the brain

define extracellular fluid in the body

also called interstitial fluid, blood plasma leaking out of gaps in the capillaries and flowing around cells to provide nutrients and collect waste

describe the travel of extracellular fluid in the lymphatic system

1. extracellular fluid collected into lymph vessels

2. carried into lymph nodes/lymph organs

3. lymph (liquid in the lymphatic system) returns to blood supply

define the blood brain barrier

property of the CNS by which it does not participate in the lymphatic system of the body as there are no holes in the blood vessels that pass through the brain and spinal cord

define the CSF

cerebrospinal fluid is extracellular fluid in the brain and spinal cord that picks out exactly what it needs from the blood

what two kinds of neurons are found in the CNS

• projection neurons

• interneurons

define the activity of projection neurons

send axon to distal area of the brain (synapse on axons far from start of the axon)

define the activity of interneurons

synapse onto close neurons

in the brain, interneurons typically release _____ and projection neurons typically release ______.

• GABA

• Glutamate

Define the two different neurons of the PNS

• sensory neurons

• motor neurons

define the activity of sensory neurons as well as their locations

detect stimuli in external and internal environment, cells bodies found in PNS, axons enter CNS

define the activity of motor neurons as well as their locations

control muscle contractions and gland secretion, cell bodies in spinal cord and brain stem and axons exit CNS

the axons of ____ neurons are efferent fibers

• motor

by which medium do the spinal cord and brain communicate to the rest of the body

nerves

define nerves

enclosed, cable like bundle of axons containing a combination of sensory and motor neurons

Humans have ____ pairs of spinal nerves, thus 1 pair for each _____, they connect to the _____. We have ____ pairs of cranial nerves connecting directly to the _____.

• 31

• vertebrae

• spinal cord

• 12

• brain

Which cranial nerve does not process movements and sensory information around the head an neck, why?

cranial nerve #10, the vagus, it branches extensively in the upper half of the body, it regulates the heart, lungs, digestive track, etc

grey matter is _____, white matter is _____

• cell bodies

• myelinated axons

afferent axons follow the (dorsal/ventral) root into the spinal cord, whereas efferent neurons follow the (dorsal/ventral) root.

• dorsal

• ventral

define the neuraxis

imaginary line running through the length of CNS

when referring to the stomach of a human and animal, which positional adjectivess would be used

human: anterior ventral

animal: inferior ventral

define lateral and medial positioning

• lateral: away from midline

• medial: close to the midline

what are the two subdivisions of the PNS

• autonomic nervous system - internal environment

• somatic nervous system - external environment

define and briefly define the two subdivisions of the efferent branch of the autonomic nervous system

• parasympathetic system - functions when body is relaxed

• sympathetic system - fight/flight/freeze, prepares the body for actions

what are the roles of the afferent and efferent fibers in the somatic nervous system

• afferent - fibers carry sensory information from body’s surface to CNS

• efferent - fibers carry motor signals from CNS to skeletal muscles

what are the roles of the afferent and efferent fibers in the autonomic nervous system

• afferent - fibers carry information from internal organs to CNS

• efferent - fibers carry information from CNS to internal organs/glands

define the major divisions of the brain and their principal structures

• forebrain (cerebral cortex, basal ganglia, limbic system, thalamus, hypothalamus)

• midbrain (tectum, tegmentum)

• hindbrain (cerebellum, pons, medulla oblongata)

define brain nuclei

collection of neighboring neurons that regulate a shared function

what are the evolutionarily oldest parts of the brain

medulla and pons

which structure of the hindbrain directly connects to the spinal cord

medulla oblongata

the _____ is a relay structure that directs information into and out of the cerebellum

pons

define area postrema and where it can be found

area of the medulla which can detect toxins via holes in the blood brain barrier and triggers vomiting

define the reticular formation

diffuse net-like network of neurons spanning the hind and mid brains and regulating things such as sleep, arousal, consciousness, etc

what would be the result of cerebellar damage

jerky, exaggerated, uncoordinated movements

what is the role of the cerebellum

coordination (but not initiation) of movement and integration of sensory and motor information

inputs to the cerebellum synapse in ____. This structure’s neurons send axons to ______. In turn, these neurons project out of the ____ to the ____.

• the superficial cerebellar cortex

• deep cerebellar nuclei

• cerebellum

• brain/spinal cord

define the function and structures of the tectum

roof structure of the midbrain formed of two top bumps called the superior colliculi, involved in orienting the animal to things in peripheral vision, and two bottom bumps called inferior colliculi involved in orienting the animal to unexpected sounds

define the function of the tegmentum

handful of brain nuclei that coordinate complex species-typical movements, as well as pain processing and behavioral response to threat