Nervous Tissue/Brain/ (Exam 3) Flashcards
Nervous system consists of the
CNS (brain and spinal cord) and PNS (Cranial and spinal nerves)
Nervous system divided functionally into
Sensory and motor systems
Receives sensation regarding the condition of the body and outside environments
Sensory system
Delivers signals to muscles and glands in body to perform an action
Motor system
Types of the sensory and motor system
Somatic and visceral
Nervous tissue is made up of
Neurons and glial cells
Receives and processes info we are aware of (touch, pan, vision, smell, hearing, taste)
Somatic sensory
Receivers and processes information that we aren’t aware of (O2 and CO2 in blood, body temperature, location of food in digestive tract)
Visceral sensory
Delivers nerve impulses to skeletal muscles (voluntary)
Somatic motor
Delivers nerve impulses to cardiac muscle, smooth muscle, and glands of body
autonomic, involuntary motor
Forms wall of heart
Cardiac muscle
Forms smooth muscle
Walls of arteries and digestive tract
Glands
Produce sweat tears mucus and saliva
Properties of neurons…
High metabolic rate, depend on constant supply of glucose and oxygen, have huge longevity, can change but can’t divide
Neurons depend on the constant supply of
Glucose and oxygen
Types of neurons
Unipolar and multipolar
What are the components of the unipolar neurons
Cell body, peripheral process, dendrites, central process, short single process
Neurons control center responsible for receiving, integrating, and sending nerve impulses
Cell body
Carries sensory information from the skin to the cell body
Peripheral process
Dendrites in unipolar neurons
Detect touch, pain, temperature, and vibration on skin
Send impulses from cell body to CNS
CENTRAL PROCESS
where the central and peripheral process attach to the cell body
Short single process
Dendrites in multipolar neurons
Conduct nerve impulses toward cell body to be processed, mainly from other neurons
Components of the multipolar neurons
Cell body, dendrites, axon, axon nillock, axon collateral, telodendria
Transmit nerve impulses away from cell body
AXON
Transition from cell body to axon
Axon nillock
Side branch of axon
Axon collateral
End of branches of axon; increase spread of effect of impulse
Telodendria
Gray matter of spinal cord is
Center of spinal cord, cell bodies and neurons
What horn is responsible for sensory and motor function
Sensory = dorsal Motor= ventral
Buldge formed by a group of cell bodies
Ganglia
Sensory information by what neurons
Unipolar neurons
Sensory information deceivers to CNS, (what information)
Afferent information
Motor information delivered to muscles and glands, what information?
Efferent information
Send impulses to motor neurons in ventral horn
Reflex
Internurons are
Multipolar Neurons and association neurons
What makes up 99% of the central nervous system
Interneurons
Motor neurons are multipolar or unipolar
Multipolar
Glial cells are loctaed in the
Cns&pns
Characteristics of glial cells
Smaller, assist neurons with their functions, physically protect and nourish neurons,
Provide framework for nervous tissue, account for half of nervous system volume
Glial cells are capable of ? Unlike neurons
Mitosis
Are there more glial or neurons
Glial cells
6 types of glial cells
4 in CNS and 2 in PNS
Glial cells in the CNS
Astrocytes, ependymal cells, microglia, and olignodendrocytes
Glial cells in PNS
Satellite cells, schwann cells (neurolemmocytes)
Star shape, processes touch capillaries and neuron parts
Astrocytes
Functions of astrocytes…
Releases calcium into fluid = storing memories
Form part of the CNS structural framework, fill in space when neurons die.
Form blood brain barriers
Controls substances that can leave capillaries and enter the fluid surrounding neurons; protects tissue of CNS from toxins
Blood brain barrier
Three specializations of blood brain barrier
- Continuous basement membrane
- Tight junctions between simple squamous cells
- Perivascular feet of astrocytes
Cubodial like ventricles of brain and central canal; have cilia to move cerebrospinal fluid
Ependymal cells
Function of ependymal cells
Ventricles contain cerebrospinal fluid (nourish the brain )
Cover capillaries lining these cavities
Form choroid plexus
Smallest slender branches extending from cell body
Microglia
Functions of microglia
Replicate in response to infection
Perform phagocytic activity and remove debris from damaged neurons
Large bulbous body and slender process
Olignodendrocytes
Olignodendrocytes functions…
Form myelin
Function of myelin
Increases conduction of velocity of neurons
Impulse traveling down an axon….
Result of reversal of polarity of the cell membrane due to calcium entering neuron
Without myelin what happens?
Reversal of polarity would go to the entire length of cell membrane (continuous conduction)
With myelin what happens…
Reversal of polarity could skip node to node (saltatory conduction)
Flat cells, around neuronal bodies
Satellite cells
Function of satellite cells
Regulate nutrient delivery and removal of waste products in neurons
Axons of multipolar cells and peripheral/ central processes of unipolar cells
Schwann cells/ neurolemmocytes
Functions of Schwann cells
Attach to portions of a neuronal process and wrap themselves around processes, laying concentric layers to for, myelin
CT surrounding peripheral nerve processes and myelin
Endoneurium
CT surrounding a fascile
Perineurium
CT surrounding a peripheral nerve
Epineurium
A glial cell tumors, can be benign or malignant
Gliomas
Immune system attacks myelin of axons in CNS, causing communication problems
Multiple sclerosis
The brain can be further divided into the
Cerebrum,brain stem, and cerebellum
Main type of neuron in the brain
Multipolar neuron
Process that sends information away from the cell body
Axon
Multipolar neurons have many _ and a single _
Dendrites and axon
Axons of most neurons are covered in
Myelin, formed by glial cells
The myelin does or doesn’t coat the entire surface of the axon
Doesn’t
The central nervous system begins development as a
Neural tube
At the 4th week of development, the cranial end develops….
Three dilutions or primary vesicles
The three dilations or primary vesicles are known as the…
Prosencephalon (forebrain), mesencephalon (midbrain), rhombencephalon (hindbrain)
At the 5th week of development of the brain, the
Primary vesicles further specialize into secondary vesicles
In the 5th week, prosencephalon gives rise to
Telencephalon and diencephalon
What retains the same name in the 5th week of brain development
Mesencephalon
In the 5th week of development, rhombencephalon gives rise to
Metencephalon and myelencephalon
The completed structures of the prosencephalon are
Cerebrum, thalamus, hypothalamus, and epithalamus
The completed structure of the mesencephalon is the
Midbrain
The completed structure of the rhombencephalon are the
Pons and cerebellum, medulla
Anterior
Front
Posterior
Back
Dorsal
Superior
Ventral
Inferior
The cerebrum consists of the
Right and left hemispheres
The hemispheres of the cerebrum are partially separated by the
Longitudinal fissure
What process is the location of conscious thought and complex intellectual function
Cerebrum
What allows us to comprehend the world around us
Cerebrum
What houses memories
Cerebrum
What allows us to be aware of sensory unpin and initiate motor activity
Cerebrum
The surface of the brain is
Convoluted (wrinkled) with gyri (hills) and sulci (valleys) to increase surface area
Gray matter can be found on the
outside of brain (cortex) or within the white matter (nuclei)
White matter in the brain is found
Deep to the cortex and contains bundles of myelinated axons
The brain and spinal cord are protected by
Bone and meninges
The meninges consist of 3 layers of connective tissue
Pia matter, arachnoid matter, dura matter
Thin layer of connective tissue adherent to the surface of the brain, following the surface of the gyri and sulci
Pia matter (delicate mother)
Located external to the pia matter, more loosely covering the brain without diving into the sulci
Arachnoid mater (webby mother )
What space is between the pia matter and arachnoid matter, and function
Subarachnoid space= contains CSF that acts as a shop absorber
Filamentous extensions of arachnoid mater called
Arachnoid trabeculae
Arachnoid trabeculae function
Anchor the arachnoid mater to the pia mater
Composed of two layers: periosteal and meningeal layer
Dura matter, tough mother
Where is the periosteal layer of the dura
Lines inside of the cranium
The meningeal layer of dura is fused to the
Periosteal layer throughout much of the skull
Extends between the cerebral hemispheres and reduces movement of the brain under the skull
Falx cerebri
The tentorium cerebelli supports the
Posterior part of the brain, with the cerebellum below
The venous blood from the brain drains mainly into….
A system of sinuses within the dura mater
The venous sinuses receive…
Deoxygenated blood from brain and deliver it to internal jugular veins
Empties into the confluence of sinuses
Superior sagittal sinus
Inferior sagittal sinus and great cerebral vein empty into the
Straight sinus
Straight sinus empties into the
Confluence of sinuses
Blood entering the confluence of sinuses goes
Left or right into a transverse sinus
The transverse sinuses become the
Sigmoid sinuses when they course inferiorly to empty into internal jugular veins
Receive blood from the ophthalmic veins in the orbit
Cavernous sinuses
The superior petrosal sinus carries blood from the
Cavernus sinus to the sigmoid sinus
The inferior petrosal sinus carries blood from the
Cavernous sinus to the internal jugular vein
The great cerebral vein is a
True vein
The dural venous sinuses have walls
composed of dura mater
The CNS forms a tube like structure called the
Neural tube
As the brain develops, the lumen develops into the
ventricular system
The ventricles of the brain contain
Cerebrospinal fluid
Function of CSF
Helps to provide nourishment for the brain
What are the lateral ventricles in the brain
C shaped, within cerebral hemispheres
Slit like ventricle between right and left diencephalon in brain
3rd ventricle
Diamond shaped ventricle in brain between brain stem and cerebellum
4th ventricle
Connections between lateral ventricles and 3rd ventricle
Inter ventricular foramina
Connection through midbrain between 3rd and 4th ventricles
Mesencephalic aqueduct
Narrow canal through center of spinal cord
Central canal
Openings in the 4th ventricle that allow CSF to flow into subarachnoid space
Apertures
CSF is derived from the
Blood vascular system by choroid plexus
Is there choroid plexus in each of the 4 ventricles of brain
Yes
CSF is continuously produced by
Choroid plexus
Approximately what mL of CSF is produced each day
500 mL
There is between what and what within the subarachnoid space at any given time
100 mL and 160 mL
CSF flows through…
Ventricular system and subarachnoid space
CSF is returned to blood into
Superior sagittal sinus
What are arachnoid villi?
One way valves that project from subarachnoid space into superior sagittal sinus, allows CSF to enter sinus
Pathological condition in which the brain swells due to build up of pressure and enlargement of ventricles.
Hydrocephalus
Major lobes of the brain
Frontal partial occipital temporal and insula
Where is the central sulcus located
Between frontal and parietal lobes
The lateral fissure helps to define the
Temporal lobe
Where does the insula lobe lie
Deep to the lateral sulcus
Primary motor cortex in the
Precentral gyrus
Control skeletal muscle activity in the opposite side of the body according to the body map.
Primary motor cortex
Causes groups of muscles to contract in a specific sequence
Premotor cortex
What’s anterior to the primary motor cortex
Premotor cortex
Motor speech area in brain, ability to speak and write
Broca’s area
Brocas area is located in the
Lower margin of the premotor cortex
Receives sensation from the skin on the opposite side of the body according to the sensory homunculus
Primary somatosensory cortex
Primary somatosensory cortex is located in the
Postcentral gyrus
Integrates the qualities of the sensory information coming into the primary somatosensory cortex in order to identify everyday objects without looking at them
Somatosensory association cortex
Processes incoming visual information
Occipital lobe
Provides conscious awareness of smells
Primary olfactory cortex (temporal)
Receives and processes auditory information
Primary auditory cortex (temporal)
Primary gustatory cortex is located in the
Insula and processes taste information
Werinckes area is found in the
Left hemisphere
Involved in the understanding written and spoken language
Werinckes area
Responsible for integrating all sensory info in order to provide context to your environment (having knowledge)
Gnostic area
Limbic system is responsible for
Emotion and memories tied to strong emotions
Map of the body on the pre central and post central gyri which indicates the relative amount of cortex devoted to the various body parts
Homunculus
Higher order functions of the brain
Encompass learning, memory, reasoning and consciousness
Where does higher order functions of the brain occur
In cerebral cortex, includes conscious and subconscious processes of information
The left side of the brain tends to handle
Language math and reasoning
The right side of the to handle
Imagination, artistic ability, insight
Axons are bundled into units called
Tracts
Association tracts interconnect
Different regions of the same hemisphere
Commissural tracts interconnect
The two hemispheres
Projection tracts link the
Hemispheres with the brain stem and spinal cord
The diencephalon includes the
Thalamus, hypothalamus, epithalamus
Diencephalon forms the walls of
The third ventricle
Diencephalon consists of several
Thalamic nuclei
What part of the brain receives, filters, and relays somatic sensory information to the cerebral cortex
Thalamus
Hypothalamus functions….
- Controls ANS
- controls endocrine system
- Regulates food and water intake
- control emotions
- Oversees circadian rhythm
The epithalamus houses the
Pineal gland, secretes melatonin
Brain stem includes
Midbrain, pons, medulla
The superior part of brain stem
Midbrain
Midbrain has a _ running through it
Cerebral aqueduct
The midbrain has pillars in the front called
Cerebral peduncles
What produces dopamine
Substantia nigra
The dopaminergic neurons effect brain processes that
Control movement and emotions
Degeneration of dopaminergic neurons leads to
Parkinson’s disease
Superior colliculi in the midbrain help…
Visually track moving objects
Inferior colliculi in the midbrain help…
Orient our senses to sound
Middle part of the brain stem
Pons
Has strong connections to cerebellum for relaying copies of motor commands from cerebrum
Pons
Inferior part of brain stem
Medulla
Contains a cardiac center and respiratory center
Medulla
Attached to the back of the brain stem
Cerebellum
The cerebellum has right and left hemisphere and folds called
Folia
Refinds skeletal muscle movements so that motion is smooth and coordinated
Cerebellum
Capable of storing memories of previously learned movements, gets a rough draft of motor commands from cerebrum and fine tunes movements, aware of body part positions
Cerebellum
Uncoordinated jerky movement due to impaired cerebellar function
Ataxia
Motor commands sent from the
Premotor cortex to spinal cord
Pons relays a copy of motor commands to
cerebellum
Cerebellum makes adjustments if movements….
To plan and send those adjustments to cerebrum
Order of CSF flow
Lateral ventricle Interventricular foremen 3rd ventricle Mesencephalic aqueduct 4th ventricle Apertures Subarachnoid space Arachnoid villi Superior sagittal sinus
Part of the brain that secretes melatonin from pineal gland
Epithalamus
