Lecture 5 Flashcards
Chapter 3
what are the 2 types of nervous systems
central nervous system (CNS) and peripheral nervous system (PNS)
what does the Central nervous system (CNS)
include
Everything in the brain and spinal cord
what does the Peripheral nervous system (PNS)
include
Any part of the nervous system outside the brain and spinal cord, including the nerves attached to the brain and spinal cord
what is the distinction between
the cns and pns
In the central nervous system, myelin is created by Oligodendrocytes
In the peripheral nervous system, myelin is created by Schwann cells.
what is Interstitial fluid
basically synonymous with extracellular fluid. It is the fluid that surrounds cells in the body.
The interstitial fluid for cells outside of the CNS comes directly from what
blood
The interstitial fluid for cells outside of the CNS comes directly from blood.
In brief how does it work
The liquid (fluid) component of blood is called blood plasma. Blood plasma can leak out of small holes, gaps in the blood vessels (blood capillaries), at which point it is called lymph.
what is The lymphatic system and how does it work
Lymph is the interstitial fluid for all cells in the body outside of the CNS.
It flows around the cells of the body picking up waste and bacteria.
Lymph is collected into lymph vessels and taken to lymph nodes/organs, which detect and destroy invading organisms and foreign particles.
Eventually lymph is returned to the circulatory system (the blood stream).
does the CNS participate in the lymphatic system
The CNS is a protected space. It does not participate in the lymphatic system
what is the Blood–brain barrier
Semipermeable barrier between the blood and the brain
if the brain needs something it will actively pull it in
do The blood capillaries that flow through the CNS have gaps in them
no gaps in them
The blood capillaries that flow through the CNS have no gaps in them.
This feature is known as what
the blood brain barrier.
Instead of using lymph (which is anything that leaks out of blood vessels), the CNS makes its own interstitial fluid called what
cerebrospinal fluid (CSF).
what is cerebrospinal fluid (CSF).
made of
It is made fresh from stuff in the blood
Cerebrospinal fluid (CSF) flows around the cells of the body doing what
picking up waste and bacteria. This fluid eventually returned to the blood.
what is the glymphatic system
The blood capillaries that flow through the CNS have no gaps in them.
This feature is known as the blood brain barrier.
Instead of using lymph (which is anything that leaks out of blood vessels), the CNS makes its own interstitial fluid called cerebrospinal fluid (CSF).
It is made fresh from stuff in the blood.
Cerebrospinal fluid (CSF) flows around the cells of the body picking up waste and bacteria. This fluid eventually returned to the blood.
This process is known as the glymphatic system.
CSF is produced in the ventricles of the brain in tissue called what
choroid plexus
CSF is produced in the ventricles of the brain in tissue called the choroid plexus.
The ventricles are connected how
interconnected hollow spaces filled with CSF.
in THE VENTRICULAR SYSTEM OF THE BRAIN how many ventricles are there
4 ventricles
what are the 4 ventricles in the THE VENTRICULAR SYSTEM OF THE BRAIN
The first two, the lateral ventricles are the largest. They sit underneath the cerebrum.
The third ventricle lies between the two thalamic nuclei.
The fourth ventricle sits between the pons and cerebellum.
how often is CSF made
CSF is made continuously and it is half replaced every three hours (the half-life).
what is The cerebral aqueduct
is a long, tube like structure that connects the third and fourth ventricle.
CSF exits the ventricles and flows around the brain and spinal cord (in the subarachnoid space) before it is absorbed into the blood supply.
what are meninges
tough, protective connective tissues that surround the brain.
what are the 3 types of meninges
The dura mater
The arachnoid membrane
The third layer that sits closest to the brain is pia mater.
what is dura mater
is the outer layer. It is thick, tough, unstretchable tissue.
what is arachnoid membrane
is the middle layer. It is soft and spongy and has a web-like appearance.
what is pia mater
The third layer that sits closest to the brain is pia mater. This layer and the space above it has blood vessels in it.
what is subarachnoid space
between the arachnoid membrane and pia mater
The subarachnoid space (between the arachnoid membrane and pia mater) is filled with what
cerebrospinal fluid (CSF).
A hollow, enclosed neural tube forms during when (the brain)
the first month of development in the womb.
A hollow, enclosed neural tube forms during the first month of development in the womb. The stem cells that make up this neural tube are called what
neural progenitor cells
Neural progenitor cells divide and multiply during the first two months of development, during a period known as what
symmetrical cell division.
At around the 2 month mark (in human gestation), symmetrical division ends and asymmetrical division starts what is this
which is when the first glial cells (radial glia) and neurons are born.
what are the 5 major divisions of the brain
forebrain: Telecephalon and diencephalon
Midbrain: Mesencephalon
Hindbrain: Metecephalon and Myelencephalon
what are the categories of Brain Development
Symmetrical Division
and asymmetrical Division
Neurogenesis
Apoptosis
what is Symmetrical Division
Division of a neural progenitor cell that gives rise to two identical progenitor cells
when does Symmetrical Division happen
Symmetrical cell division of neural progenitors cells occurs during the first two months of development in the womb. Symmetrical division ends when asymmetrical division starts. Neural progenitor cells hug the inside ring of the neural tube in an area called the ventricular zone
what is Asymmetrical Division
Division of a neural progenitor cell that gives rise to another progenitor cell and a new glial cell or new neuron
when does Asymmetrical Division
happen
In nervous system development, the period of asymmetrical division that gives birth to all the neurons in the brain lasts for about 2 to 3 months. More neurons are born during this time than will be present at birth.
what is Neurogenesis
Production of new neurons
when does Neurogenesis happen
Neurons are born from the asymmetrical cell division of neural progenitor cells (stem cells). Most neurogenesis stops 4 to 5 months into development, however the adult brain retains some stem cells that continue to divide and produce neurons throughout life, particularly in the hippocampus
what is Apoptosis
a process of programmed cell death that occurs I multicellular organisms
when does Apoptosis
happen
a highly regulated and controlled form of cell suicide that ensures that the contents of a dying cell do not disrupt its neighbours. The process of asymmetrical cell division that supports neurogenesis in the developing brain ends when neural progenitor cells undergo apoptosis
what are the ANATOMICAL DIRECTIONS
Neuraxis Anterior (rostral) Posterior (caudal) Dorsal (superior; Ventral (inferior; Lateral (distal, Medial (proximal,
what is Neuraxis
An imaginary line that runs along the length of the CNS
what is Anterior (rostral)
Front end or toward the head
what is Posterior (caudal)
Tail end
what is Dorsal (superior)
Top of the head and towards the back
what is Ventral (inferior
towards the belly)
Front surface that faces the ground
what is Lateral (distal
away from the midline) Toward the side
what is Medial (proximal
close to the midline)
Toward the middle
what is Sagittal plane
A mid-sagittal cut means the exact middle (between the eyes)
what is Medial
toward midline
what is Lateral (
away from midline)
what is Transverse plane
(frontal section, cross section, coronal section)
like a cut dividing front of brain and back of brain
define Contralateral
Structures on opposite side of the body
(e.g. the motor cortex controls contralateral muscles. When we say the left motor cortex controls movement of the contralateral hand, we mean it controls movement of the RIGHT hand.)
define Ipsilateral
Structures on same side of body
(e.g. the olfactory bulb sends axons to the ipsilateral hemisphere, meaning that the left olfactory bulb sends axons to the left hemisphere. Olfaction and taste are the only sensory systems that do not have contralateral organization.)
define Superficial
Close to the surface, close to the exterior
define Deep
Far away from the surface, deep in the interior of the organism
what is included in The Hindbrain
Cerebellum, Pons and Medulla Oblongata
where is The hindbrain
the most posterior division of the brain.
where is the Medulla Oblongata an what does it do
the most caudal part of the brain stem. It also contains a part of the reticular formation and nuclei that control vital functions of respiration and the cardiovascular system
what is the Area postrema
famous area of the medulla, since it is one region where the blood–brain barrier is weak. Poisons can be detected there and it can initiate vomiting.
where is The pons and what does it do
large bulge in the brain stem that contains a relay with the cerebellum. At its core is the reticular formation, which plays an important role in sleep and arousal.
where is The cerebellum and what does it do
(known as ‘little brain’) is a convoluted mass of cortex involved in the integration of sensory perception and motor control.
Damage to cerebellum does what
impairs standing, walking, or performance of coordinated movements
Cerebellar damage results in jerky, poorly coordinated, exaggerated movements; extensive cerebellar damage makes it impossible even to stand
The cerebellum does what
contributes to coordination, precision, and accurate timing. It integrates sensory information and motor commands to exert a coordinating and smoothing effect on movement.
what is included in The Midbrain
Tectum and Tegmentum
where is The Midbrain
surrounds the cerebral aqueduct and consists of two major parts: tectum and tegmentum
where is The Tectum
(“roof”) appear as two pairs of bumps on the dorsal surface of brain stem
what does The Tectum do
The Tectum (“roof”) appear as two pairs of bumps on the dorsal surface of brain stem. These bump reflect the superior colliculi and inferior colliculi, which have visual and auditory functions, respectively
what is included in The tegmentum and what does it do
The tegmentum (“covering”) includes several structures including the rostral reticular formation, the periaqueductal gray, the red nucleus, and the substantia nigra. These structures are involved in sleep, arousal, attention, movement and reflexes
what is included in THE FOREBRAIN
HYPOTHALAMUS and thalamus and LIMBIC SYSTEM
CEREBRAL CORTEX
Basal ganglia
limbic system
what structure is The hypothalamus
a two lobed structure made up of several nuclei
what does the hypothalamus control
Some control autonomic and endocrine responses (e.g. drinking and sleeping).
In general, these nuclei organize behaviours that are directly related to survival, i.e. the four F’s: feeding, fighting, fleeing and mating.
Some hypothalamic neurons stimulate the pituitary gland which releases hormones in reproductive physiology and behaviour
what are hormones job
Non-synaptic, long distance Chemical Communication
define Hormone
Chemical substance that is released by an endocrine gland and that has effects on target cells in other organs
what is Endocrine gland
Gland that secretes chemical signals (hormones) into the bloodstream. Much of endocrine system is controlled by hormones produced by cells in hypothalamus
what is The thalamus
two lobed structure is divided into several nuclei. Some are sensory relay nuclei; they receive sensory signals and relay them to different regions of the cerebral cortex.
E.g. the lateral geniculate nuclei of the thalamus receive information from the eye and send axons to the primary visual cortex. The medial geniculate nuclei relay auditory information.
Nuclei of the thalamus have widespread cortical projections
where is the LIMBIC SYSTEM
THE FOREBRAIN
Internal sensations (stretch) and internal muscles (heart rate, breathing) mostly get processed where
in hindbrain
Sensory information (touch, taste, hearing, vision) goes to the what first
thalamus
Sensory information (touch, taste, hearing, vision) goes to the thalamus first. The thalamus then relays this information to where
appropriate primary sensory area in cerebral cortex.
Motor information goes from where to where
primary motor cortex down to spinal cord and then to muscles
Motor information goes from primary motor cortex down to spinal cord and then to muscles. Areas in the midbrain and hindbrain (including cerebellum) strongly contribute to what
movement-related processes
what is another name for The telencephalon
the cerebral hemispheres
The telencephalon (the cerebral hemispheres) is one of the two major portions of the forebrain. On the surface of the cerebral hemispheres is the cerebral cortex, which is highly convoluted with what
sulci (small grooves)
fissures (large or major grooves)
gyri (ridges between sulci or fissures).
what do The convolutions to the surface area of the cerebral cortex.
they increase it
The outermost portion of the cerebral cortex is called what
gray matter
why is The outermost portion of the cerebral cortex gray matter
The color is because of the high concentration of cell bodies there
what matter is below the grey matter
The white matter
The white matter (beneath the gray matter) has a large concentration of what
myelinated axons. There are very few cell bodies in this area
Although two cerebral hemispheres perform somewhat different functions, perceptions and memories are unified. This unity is accomplished by what (in the cerebral cortex)
corpus callosum, a large band of axons that connects corresponding parts of association cortex of the left and right hemispheres
what are the main areas of the cerebral c
The primary motor cortex (frontal lobe).
The somatosensory cortex (parietal lobe)
The primary visual cortex (occipital lobe)
The primary auditory cortex (temporal lobe)
The insular cortex (in lateral fissure b/t lobes)
what is another name for The primary motor cortex
frontal lobe
what does The primary motor cortex (frontal lobe) do
sends motor information to muscles
what is another name for The somatosensory cortex
parietal lobe
what does The somatosensory cortex do
receives touch information. Different regions of the somatosensory cortex receive information from different parts of the body (e.g. feet, hands, fingers).
what is another name for The primary visual cortex
occipital lobe
what does The primary visual cortex do
receives visual information.
what is another name for The primary auditory cortex
(temporal lobe)
what does The primary auditory cortex do
receives auditory information.
what does The insular cortex (in lateral fissure b/t lobes) do
receives gustatory information
Each primary sensory area of the cortex sends information to adjacent regions called what
sensory association cortex
what does the Sensory Association Cortex
do
Perception takes place there and memories are stored there
Regions of the association cortex located closest to primary sensory areas receive information from only one sensory system
what are The basal ganglia
a collection of subcortical nuclei in forebrain, which lie beneath the anterior portion of lateral ventricles. (In the brain, the word nuclei means a group of neurons of similar shape.)
what are the parts to the basal ganglia
The caudate nucleus
The putamen
The globus pallidus
where is the The caudate nucleus located
is located in the centre of the brain. It resembles a C shape with a wide head in the front tapering to a body and a tail at the end.
where is the putamen
is located in the centre of the caudate. Together, the caudate and putamen have a striped appearance and are know together as the striatum.
where is The globus pallidus and what does it do
is a spherical shaped structure that receives input from the caudate and putamen
The basal ganglia are involved in what
control of movement. For example, Parkinson’s disease is caused by degeneration of certain neurons located in the midbrain (dopamine neurons) that regulate basal ganglia activity via projections to the caudate and putamen.
what is The Spinal Cord
Long, conical structure, approximately as thick as an adult’s little finger
what does The Spinal Cord do
Principal function of the spinal cord is to distribute motor fibers to the effector organs of the body (glands and muscles) and to collect somatosensory information to be passed on to the brain
is the Spinal cord autonomous from the brain
Spinal cord also has a certain degree of autonomy from the brain; various reflexive control circuits are located there
what is Afferent
Going towards the CNS
what is Efferent
Going away from the CNS
The brain and spinal cord communicate with the rest of the body via what nerves
cranial nerves and spinal nerves
cranial nerves and spinal nerves are part of what system
peripheral nervous system
what does the peripheral nervous system do
conveys sensory information to central nervous system and conveys messages from central nervous system to body’s muscles and glands
how many cranial nerves are attached to ventral surface of brain
12 pairs
Twelve pairs of cranial nerves are attached to ventral surface of brain
Most of these nerves serve as what
sensory and motor functions of head and neck region
Twelve pairs of cranial nerves are attached to ventral surface of brain
Most of these nerves serve sensory and motor functions of head and neck region
The exception to this rule is what
the vagus nerve (tenth cranial nerve), which is called the vagus (“wandering”) because its branches wander throughout thoracic and abdominal cavities. It regulates functions of the heart, lungs, upper digestive track, and other organs in that area.
what is the peripheral nervous system broken down to
somatic and auomatic
what does the somatic nervous system do
Interacts with external
environment
what does the autonomic nervous system do
Regulates body’s internal
environment
what do the Afferent nerves of the somatic system do
Carry sensory signals from eyes, ears, skin, etc TO CNS
what do the Afferent nerves of the autonomic system do
Carry sensory signals from internal organs TO CNS
what do the Efferent nerves of the somatic system do
Carry motor signals FROM
CNS to skeletal muscles
what do the Efferent nerves of the autonomic system do
Carry motor signals FROM
CNS to internal organs
what is the Somatic nervous system
Part of peripheral nervous system which receives sensory information from the sensory organs and controls movements of skeletal muscles. In general, the somatic system interacts with the external environment
what is the Autonomic nervous system (ANS)
other branch of peripheral nervous system concerned with regulation of smooth muscle, cardiac muscle and glands. In general, the ANS interacts with the body’s internal environment
The ANS consists of two anatomically separate systems: what are they
the sympathetic division and the parasympathetic division.
what is the Sympathetic division
Part of autonomic nervous system supports activities associated with increases in energy expenditure; the “fight or flight response (e.g., increases in heart rate, blood flow, blood sugar).
what is the Parasympathetic division
Part of autonomic nervous system supports activities that that occur during relaxed state and are involved with increasing in the body’s energy stores (digestion).
These activities include digestion, sexual arousal, defecation, urination, and salvation (i.e., both “feed and breed” and “rest-and-digest” activities
what are the cells of the nervous system
sensory neuron
motor neuron
interneuron
what is the Sensory neuron
Neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system
what is the motor neuron
A neuron located within the central nervous system that controls the contraction of a muscle or the secretion of a gland
what is the Interneuron
A neuron located entirely within the central nervous system
only send axons very locally with a brain area
what are projection (rely) neurons
send axons outside of local area
