Chapter 7,8,9 Flashcards
Which component of the endocrine system produces the body’s major metabolic hormone? and what two hormones?
Thyroid gland (thyroid hormone- stimulates the metabolic rate)
and
(calcitonin- decreases blood calcium levels, stimulates osteoblasts in bone to take Ca+2 from the blood and deposit it in bone matrix) this hormone is antagonistic to parathyroid hormone
found at base of the throat and has 2 lobes and a connecting isthmus
the thyroid hormone
What has four small masses on posterior of the thyroid gland? what hormone does this gland secrete?
parathyroid glands
PTH (Parathyroid hormone-increases blood calcium levels, stimulates osteoclasts to release Ca+2 from bone matrix, stimulates kidneys and intestine to absorb more Ca+2) antagonistic to calcitonin
regulates blood calcium levels
what secretes insulin and glucagon to regulate blood glucose levels and where is it located
the pancreas- located in abdomen, close to stomach
mixed gland and has both endocrine and exocrine functions
alpha cells release glucagon
beta cells release insulin
What is the size of a pea, protected by the sphenoid bone, connected to hypothalamus by —- stalk? Hormone it releases is controlled by hypothalamus. It has 2 functional lobes
anterior pituitary gland- glandular tissue: secretes 6 hormones
posterior pituitary-nervous tissue secretes 2 hormones
How are blood levels of most hormones kept within a narrow range ?
negative feedback: which is a homeostatic mechanism. endocrine gland secretes hormone until it receives a feedback signaling the gland to inhibit hormone secretion
what involves nerve fibers directly stimulating hormone release from an endocrine gland?
neural stimuli,
most endocrine glands respond to hormonal or humoral stimuli
one of the cell mechanisms hormones act through is
(H-R)hormone receptors binding initiates a series of reactions that result in the activation of enzymes and changes in metabolism.
second-messenger system
They are used by protein, peptide, and amine hormones which are water soluble. so must bind to receptor
this results in synthesis of new proteins, used by steroid hormones. they are lipid soluble
direct gene activation
all steroids use gene activation
what releases insulin in response to high blood glucose levels?
produced by beta cells of pancreatic islets
actions: lowers blood sugar level and stimulate the uptake of sugar by body cells, especially liver, adipose, and skeletal muscle cells
what releases glucagon in response to low blood glucose levels produced in pancreatic islets
alpha cells - raises blood sugar level and stimulates the release of stored sugar from liver
glucagon increases blood glucose levels by stimulating the liver to break down stored glycogen into glucose and release that glucose into the blood
the hormone that simulates the contraction of smooth muscle in the uterus is
oxytocin, oxytocin also initiates milk ejection during lactation
what triggers ovulation and ovarian production of estrogens and progesterone in women?
luteinizing hormone, this stimulates testosterone production in men
what promotes maturation of ovarian follicles and stimulates production of eggs and sperm
follicle stimulating hormone, in men it stimulates sperm production
the posterior pituitary stores and releases which hormones?
(oxytocin-stimulates uterine contractions)OT
(antidiuretic hormrone, produced by the hypothalamic neurons- stimulates water retention by the kidneys) ADH
what does the anterior pituitary gland produce and release?
(prolactin-stimulates milk production)PRL
(growth hormone-stimulates growth, especially in bones and muscles) GH
(Thyroid-stimulated hormone - stimulates thyroid gland to secrete thyroid hormone)TSH
(adrenocorticotropic hormone-stimulates the adrenal cortex to secrete glucocorticoids like cortisol) ACTH
(follicle-stimulating hormone-stimulates the production of sperm and eggs) FSH
(luteinizing hormone-stimulates the testes and ovaries) LH
what hormone produced by the placenta loosens pelvic ligaments prior to birth
relaxin
what triggers ovulation of an egg from the ovary and stimulates testosterone production in the testes
(luteinizing hormone-stimulates the testes and ovaries) LH
an anterior pituitary hormone
where are the parathyroid glands located
posterior surface of the thyroid gland, they release parathyroid hormone in response to low blood calcium ion levels
where is the thymus located and what hormone does it secrete for what?
anterior to heart and posterior to the sternum
largest in infants and children
Secretes thymosin-involved with the development of the immune system
ON the the superior surface of each kidney (suprarenal glands)
has 2 regions
Adrenal glands
(adrenal cortex-outer 80-90% of gland)
(adrenal medulla- inner 10-20% of gland, nervous tissue
what secretes nonhormonal substances into ducts that empty onto a membrane surface
exocrine glands, such as salivary glands and sweat glands
what are the gonadotropic hormones
luteinizing hormone and follicle stimulating hormone
what causes acromegaly a condition in which the bones of the face, hands and feet enlarge and widen
hypersecretion of growth hormone in an adult
what is it called when there is hyposecretion of growth hormone, gigantism
Has three layers that secrete different steroid hormones in region of adrenal glands
adrenal cortex
Mineralocorticoids (mainly aldosterone) stimulates Na+ retention and K+ elimination by the kidneys
glucocorticoids (mainly cortisol) stimulates increase in blood sugar level in response to long-term stress
Sex hormones- low levels of androgens and estrogens
which hormone from the adrenal cortex targets the kidney tubules by stimulating the retention of sodium ions and secretion of potassium ions into the urine?
aldosterone
where is thyroid gland located
in the anterior neck just inferior to the voice box
a hormone that works by direct gene activation must be
lipid soluble
which hormone is the most important regulator of blood calcium ion levels
parathyroid hormone
a current that is continuously regenerated along the length of the axon and does not die out
action potential
the part of the PNS that sends sensory input to the CNS from sensory receptors around the body
afferent (sensory division)
Sensory (afferent) neurons
Structure: most unipolar; some bipolar
Cell bodies in ganglia
Carry impulses from the sensory receptors to
the CNS
the middle layer of the meninges, had weblike extensions attach to the inner layer, the pia mater
arachnoid mater
nervous tissue support cells
abundant, start shaped cells
form barrier btwn capillaries and neurons
control the chemical environment of the brain
astrocytes
what is a stimulus
a change in the environment
what is the master controlling and communicating system of the body
fasting acting, skeletal muscles contract;; exocrine glands secrete
nervous system: it uses nerve impulses and neurotransmitters
what are the functions of the nervous system
3 overlapping functions
Sensory input
To monitor changes (stimuli) occurring
inside and outside the body
Gather information
Integration
Process and interpret sensory input
Decide if action is needed
Motor output
Response to integrated stimuli
Activates muscles or glands
what gathers information and monitors changes, stimuli occuring inside and outside the body
sensory input
what is the process and interpret sensory input and decide if action is needed
integration
what response to integrated stimuli and activate muscles to contract or glands secrete
motor output
PNSperipheral nervous system
Nerves and ganglia
Nerve = bundle of neuron fibers (axons)
Cranial nerves arise from brain
12 pairs
Vagus (CN X) – main parasympathetic nerve
Spinal nerves arise from spinal cord
31 pairs of mixed nerves
Carry both sensory and motor fibers
Ganglion – cluster of neuronal cell bodies in PNS
what is the region that initiates action potential (impulses)
trigger zone
what is a neurons ability to respond to stimuli and convert it into an action potential (nerve impulse)
irritability
what is a neurons ability to transmit an impulse and send signal to next cell
conductivity
what part of nervous system monitors changes (stimuli) occurring in side and outside the body
gathers information
sensory input (on afferent pathway)
what part of nervous system responds to integrated stimuli
and activates muscle or glands
motor output to an effector like skeletal muscle
what is the structural classification of nervous system
Structural Classification
Central Nervous System
(CNS)
Brain and Spinal Cord
Peripheral Nervous System
(PNS)
Nerves outside the
brain and spinal cord
Cranial and spinal
nerves
what is central nervous system composed of
brain and spinal cord
what is the peripheral nervous system composed of
cranial nerves and spinal nerves
in the sensory division
what carries information from peripheral Nervous system to the central nervous system
nerve fibers
what are the two subdivisions of the motor division (efferent)
somatic nervous system: voluntary, skeletal muscle
autonomic nervous system
involuntary, smooth muscle cardiac muscle glands
what are the effectors of the autonomic nervous system?
smooth muscle, cardiac muscle, and glands
what does nervous system consists of
neurons and neuroglia
(6types of glial cells)
oligodendrocytes
schwann cells
ependymal cells
astrocytes
microglia
satellite cells
what are structural and functional differences between neurons and neuroglia
neurons are the structural and functional unit of the nervous system and conduct nerve impulse
neuroglia are support cells that provide physical support insulation and nutrients to neurons
what is another name for nerve impulses?
action potentials
what is most abundant glial cell? star shaped cells
touch capillaries and neuron
astrocytes
what does blood brain barrior do by the astrocytes
forms a barrier btwn capillaries and neurons and controls the chemical environment of the brain
Includes the least permeable capillaries of the
body
Excludes many potentially harmful substances
Useless as a barrier against some substances
Fats and fat soluble molecules
Respiratory gases (CO2 and O2)
Alcohol
Nicotine
Anesthesia
nervous tissue support cells
phagocytose bacterial cells and cellular debris in the CNS
microglia
what lines the cavities of the brain and the central canal of the spinal cord and circulate cerebrospinal fluid
ependymal cells
what wraps around nerve fibers (axons) in the CNS and produce myelin sheaths made of nervous tissue support cells
oligodendrocytes
In CNS, oligodendrocytes
form the myelin sheath
No neurilemma
nervous tissue support cells that protect neuron cell bodies in ganglia of the peripheral nervous system
satellite cells
other glial cell found in PNS that form myelin sheath around axons in the peripheral nervous system like a jelly roll fashion
schwann cells
Axons are either myelinated or
unmyleinated
Unmyelinated axon
Schwann cell surrounds
region of several axons
Myelinated axons
In PNS, Schwann cells wrap
around peripheral axons in
jelly-roll fashion
Layers of cell membrane
create myelin sheath
Whitish, fatty material
Neurilemma
Portion of Schwann cell
that contains most of the
cytoplasm and nucleus
n CNS, oligodendrocytes
form the myelin sheath
No neurilemma
cells specialized to transmit nerve impulses or action potential. the 3 major regions of have a cell body, dendrites, axon
neurons=nerve cells
what is another name for cell body
soma
anatomy of cell body
nucleus
large nucleolus
nissl substance
neurofibrils
what is the specialized rough endoplasmic reticulum of the cell body
nissl substance
what helps maintain cell shape of cell body
neurofibrils
what is short highly branched cytoplasmic extensions that conduct signoals toward the cell body
dendrites
what only has one neuron, arises from the axon hillock and may have branches, collaterals
and a
trigger zone
axon
what contains vesicles with neurotransmitters
axon terminals
what is gap separated from one neuron to next
synaptic cleft, gap btwn adjacent neurons
transmission of a signal at synapses
Impulses are not directly able to cross the synapse to
another neuron
1. Action potential causes synaptic vesicle to move
to membrane
2. Neurotransmitter is released from axon terminal
3. Neurotransmitter diffuses across synaptic cleft
4. Neurotransmitter binds to receptor channel on
the dendrite or soma of the postsynaptic neuron
5. Receptor channel opens
6. Na+ entering postsynaptic neuron helps neuron
reach threshold and generate an action potential
How does nervous system function? the process?
Functional Classification
Sensory (afferent) division
Nerve fibers that carry
information to the central
nervous system
Motor (efferent) division
Nerve fibers that carry
impulses away from the
central nervous system
what are the two control systems in the body
nervous system and endocrine system
slow acting control system could take minutes to hours to days as well as turning off; controls metabolism of virtually all cells; uses hormones (chemical messenger)
endocrine system
what are some major hormonal actions
regulation of metabolism
maintenance of homeostasis
mobilzation of body defenses
growth and development
reproduction
what are ductless glands;
produce hormones and secrete hormones into the blood, and have a rich blood supply, formed from epithelial tissue
endocrine glands
what only has cells with the appropriate receptors are affected by a specific hormone;
H-R (Hormone receptor binding initiates a cellular response
Blood transports hormones to these
target cells: it has a receptor for a specific hormone
what are the 3 groups of chemical classification of the chemistry of hormones
amino acids-proteins; peptides; amines (structure based on amino acids)
steroids-made from cholesterol
prostaglandins-made from lipids (secreted by virtually body cells) classified as local hormones meaning the target cells are neighboring cells. ex: inflammation, fever, blood clotting, gastric secretions
what are hormones made from proteins, peptides, amines
amino acids
what are the hormones made from cholesterol
steroids
what are the hormones made from lipids secreted by virtually all body cells;
prostaglandins
what are the mechanisms of hormones action. what activates genes so proteins are synthesized?
steroid hormones
What is irritability
The ability to respond to stimuli and convert it into an action potential
What is conductivity
Ability to transmit an impulse and send signal to next cell
Membrane potential
Means voltage.
It is a difference in charge btwn the extracellular fluid and the intercellular fluid
Potential difference across cell membrane
Plasma membrane is polarized at rest
Fewer positive ions are inside the cell than
outside the cell
Resting membrane potential (RMP) varies with
cell type
-40 to -90 mV
Membrane potential is due to
Distribution of ions across plasma membrane
[Na+] high outside cell; low inside
[K+] low outside cell; high inside
Negatively charge molecules
DNA, RNA, proteins
Membrane permeability to Na+ and K+
Na+/K+ pump (3Na+ out: 2K+ in)
At resting what is membrane considered
Polarized membrane potential
Outside is positive and inside negative because fewer positive ions are inside the cell than outside the cell
Resting membrane potential
The voltage difference at resting varies with cell type
-40 to -90 mV
Resting Membrane potential for sodium and potassium is due to
Distribution of ions across plasma membrane
Na+ high outside cell; low inside
K+ low outside cell; high inside
DNA, RBA, proteins contribute to resting membrane potential because
Negatively charged molecules
What contributes to membrane potential in resting neuron
What is depolarization and repolarization
Membrane Potential Changes
Depolarization
Membrane potential becomes less
negative (more positive)
Na+ channels open; K+ channels closed
Na+ enters cell sodium defuses into the cell
sodium enters the cell
at peak of action potential the sodium channels close
Repolarization
Membrane potential returns to RMP
K+ channels open; Na+ channels closed
K+ leaves cell
What is repolarization
when membrane potential returns to resting membrane potential or RMP
what happens is k+ potassium channels open, and Na+ sodium channels are closed
What is an action potential
Rapid sequence of depolarization and repolarization
Resting potential of a neuron
-70
Threshold potential
Membrane potential at which an action potential is generated
Stimuli from other neurons sum to bring membrane to threshold
For a neuron threshold potential is
-55mV
What is the peak voltage of action potential for a neuron
+10mV
Where is action potential will be initiated at
The trigger zone of an axon
If the action potential is generated it is propagated over the entire action
Begins at trigger zone to end at axon terminals
how are action potentials conducted down the axon
depends whether it is myelinated or unmyelinated
On myelinated axons
Action potentials occur only at nodes of
Ranvier
Saltatory conduction: AP appears to jump
from node to node
Relatively fast: 120 m/sec
On unmyelinated axon
Action potential travels along entire
plasma membrane
Relatively slow: 0.5 m/sec
AP appears to jump from node of ranvier to node of ranvier
saltatory conduction, relatively fast 120m/sec on myelinated axon
What is the membrane potential at which the action potential is generated
an action potential is generated when a stimulus changes the membrane potential to the values of threshold potential. The threshold potential is usually around -50 to -55 mV.
conduction on unmyelinated axon
action potential travels along entire plasma membrane
relatively slow .5m/sec slow for action potential
neurons not in direct physical contact with cell that it stimulate or innervates
the fluid filled space btwn axon terminal and membrane
synaptic cleft is the name of the gap
post synaptic neuron transmits to?
can be dendrites or cell body, covered with synapses
what is junction btwn 2 neurons
synapse
transmission of the signal at synapses steps or events at a synapse
impulses are not directly able to cross the synapse to another neuron, transmission involves neurotransmitter
- AP causes synaptic vesicle to move membrane
2.neurotransmitter is released from axon terminal
3.neurotransmitter diffuses across synaptic cleft
4.neurotransmitter binds to receptor channel on the dendrite or soma of the postsynaptic neuron
5.receptor channel opens
6.Na+ entering the post synaptic neuron reaching threshold and generated an action potential
To stop signal:
1. Presynaptic neuron stops releasing
neurotransmitter
2. Neurotransmitter diffuses away from cleft, is
broken down, or is taken up into axon terminal
how do we stop a signal of transmission of signal at synapses
1.presynaptic neuron stops releasing neurotransmitter
2.neurotransmiter diffuses away from cleft, is broken down, or is taken up into axon terminal and recycled
where are neurotransmitters stored
within synaptic vesicles
what is a physiology reflexes
Rapid, predictable and involuntary response to stimuli
Somatic reflexes
Reflexes that stimulate the skeletal muscles
Example: pulling your hand away from a hot object
Autonomic reflexes
Regulate the activity of smooth muscles, the heart,
and glands
Example: regulation of smooth muscles, heart and
blood pressure, glands, digestive system
refexes that stimulate the skeletal muscles, example pulling hand away from hot object
somatic reflexes
regulate the activity of smooth muscles, the heart, and glands. ex ample:regulation of smooth muscles, heart and blood pressure, glands, digestive system
autonomic reflexes
components of a typical reflex arc
Example: flexor (withdrawal) reflex called three neuron reflex arc
Two-neuron reflex arcs
Simplest type
Example: patellar (knee-jerk) reflex
five elements of a reflex
1. sensory receptor-reacts to a stimulus
2.sensory neuron-carries message to the integration center
3.integration center-(CNS; interneuron) processes information and directs motor output
4. motor neuron-carries message to an effector (form of AP)
5. effector organ- is the muscle or gland to be stimulated
what happens in a three-neuron reflex arc
or identify the elements of a reflex in the correct order
consists of five elements
1. receptor
2.sensory neuron
3.interneuron
4.motor neuron
5.effector
what are the layers that protect the central nervous system
1st layer-scalp and skin
skull and vertebral column
meninges
cerebrospinal fluid (CSF)
blood-brain barrier
what are the meninges layers, 3 connective tissue membranes covering and protecting brain and spinal cord
dura mater-very tough
arachnoid mater
pia mater-on surface on brain and spinal cord
what is the fluid surrounding brain and spinal cord
cerebrospinal fluid (CSF)
Similar to blood plasma composition
Formed by the choroid plexus; resorbed by
arachnoid villi
Forms a watery cushion to protect the brain
Circulated in subarachnoid space, ventricles, and
central canal of the spinal cord
double-layered external covering
separates to form dural sinuses filled with venus blood
dura mater
middle layer
web-like
arachnoid mater
clings to surface of brain and spinal cord
contain superficial blood vessels
pia mater
space between arachnoid and pia mater filled with cerebrospinal fluid
subarachnoid space
what covers brain and spinal cord?
meninges
Dura mater
Double-layered external covering
Separates to form dural sinuses
Arachnoid layer
Middle layer
Web-like
Pia mater
Clings to surface of brain and spinal cord
Contain superficial blood vessels
Subarachnoid space
Space between arachnoid and pia mater
Filled with cerebrospinal fluid
how many layers is the dura mater in the spinal cord
1
what is space between meninges surrounding spinal cord and bones of the vertebral canal, filled with adipose tissue and loose connective tissue
epidural space
space surround the dura mater
similar to blood plasma composition
formed by the choroid plexus
resorbed by arachnoid villi
forms a watery cushion to protect the brain
cerebrospinal fluid(CSF)
formed within the ventricles
circulated in subarachnoid space
4 interconnected cavities within brain filled with CSF
ventricles
(2lateral, 3rd and 4th ventricles)
Ventricles
4 interconnected cavities within brain filled
with CSF (2 lateral, 3rd and 4th ventricles)
what structure makes cerebrospinal fluid
choroid plexus
includes the least permeable capillaries of the body
excludes many potentially harmful substances
useless as a barrier against some substances
blood-brain barrier
what are some useless as a barrier against some substances
fats and fat soluble molecules
respiratory gases (co2 & o2)
alcohol
nicotine
anesthesia
what are the 4 major portions for the brain
4 major portions
Cerebrum (cerebral hemispheres),
diencephalon, brain stem, cerebellum
includes more than half of the brain mass
Three main regions of cerebrum
Gray matter — outer layer in the cerebral
cortex composed mostly of neuron cell bodies
White matter —composed of myelinated axons
Basal nuclei — regions of gray matter buried
within the white matter
cerebrum
outer layer in the cerebral cortex composed mostly of neuron cell bodies in the cerebrum
and unmyelinated fibers
gray matter
Internal gray matter is mostly cell bodies
Dorsal (posterior) horns
Anterior (ventral) horns
Gray commissure surrounds the central canal
Central canal is filled with CSF
composed of myelinated axons in the cerebrum
white matter
Exterior white mater — fiber tracts
Ascending tracts
Carry sensory information to brain
Descending tracts
Conduct motor impulses from brain to
motor neurons
regions of gray matter buried within the white matter of cerebrum
basal nuclei
what is the thin layer of gray matter on the surface of the brain called
cerebral cortex
midsaggital line the longitudinal fissure divides the cerebrum into 2 hemispheres
Cerebrum divided into 2 hemispheres
Paired (left and right) superior parts of the
brain
Connected internally by corpus callosum
Surface is made of ridges (gyri) and grooves
(sulci)
in the cerebrum what is an area that is the Primary motor area
Voluntary control of skeletal muscles
Sends impulses to skeletal muscles
Broca’s area - “motor speech”
Involved in our ability to speak
Problem solving; working memory; judgment
Language comprehension region
primary motor area in the frontal lobe
in the cerebrum what is an area that is involved in our ability to speak
broca’s area-motor speech also in the frontal lobe
vision area in the cerebrum, everything involved with vision
occipital lobe
in the cerebrum the fiber tracts-bundles of myelinated axons, deep to grey matter
white matter
what are bundles of myelinated axons
fiber tracts
what is the largest fiber tract that connects hemispheres of the cerebrum
corpus callosum
regulate skeletal muscle movements (starting and stopping activity
basal nuclei
what sits on top of the brain stem, enclosed by the cerebral hemispheres, main parts thalamus and hypothalamus
deep to 2 cerebral hemispheres
diencephalon
the relay station for sensory impulses;
transfers impulses to the correct part of the cortex for localization and interpretation
what surrounds the third ventricle;
thalamus
where is hypothalamus located in the body and what does it do?
below the thalamus,
important autonomic nervous system center;
helps regulate body temp, controls water balance,
regulates metabolism;
important part of the limbic system (emotions);
regulates secretions of hormones from pituitary gland
which part of the brain is a relay station for sensory information
thalamus
Surrounds the third
ventricle
The relay station for
sensory impulses
Transfers impulses to
the correct part of the
cortex for localization
and interpretation
what attaches to the spinal cord, and has midbrain, pons, medulla oblongata
parts of brain stem
mostly composed of tracts of nerve fibers;
reflex centers for vision and hearing in the brain stem
midbrain
mostly fiber tracts;
modifies activity of respiratory centers in the medulla
pons
what important control centers that control heart rate ; blood pressure regulation ;breathing (respiratory center-set basic rate and depth of breathing); swallowing and vomiting
medulla oblongata
the lowest part of the brain stem;
merges into spinal cord (has tracts); contains important control centers
coordinates skeletal muscle activity; helps maintain posture; balance and equilibrium
cerebellum
Slender column of nerve fibers (tracts) and neurons
Center for spinal reflexes
Surface anatomy
Occipital bone to the 1st or 2nd lumbar vertebra
(L1-L2)
31 pairs of spinal nerves
Cauda equina is a collection of spinal roots at the
inferior end
Anterior median fissure
Posterior median sulcus
spinal cord
how many pairs of spinal nerves are there in the spinal cord
31pairs
what is a collection of spinal roots or cluster of nerve roots at the inferior end of the spinal cord
cauda equina
a deep groove; on the front surface of spine; anterior on the midline
anterior median fissure
shallow groove on the midline on the posterior spinal cord
posterior median sulcus
at what vertebral level does the spinal cord end
L1
which type of matter is on the exterior of spinal cord
exterior white matter
sensory fibers; cell bodies of these neurons found in the dorsal root ganglia
dorsal (posterior) roots
contains motor fibers; cell bodies of these motor neurons are found in the anterior horn
ventral (anterior) roots
what type of fiber is located in the posterior roots
sensory fibers
what conducts signal away from cell body toward axon terminal
axon
when membrane potential becomes more positive or less negative
depolarization
what is the end of axon called
axon terminal
what is the specialized RER found in a neuron
nissl substance
what are the phagocytic cells found in CNS called
microglia
what produce myelin sheath in CNS
oligodendrocytes
brain and spinal cord
central nervous system
form myelin sheath in PNS
schwann cells
conduction of an action potential in a myelinated axon
saltatory conduction
rapid, involuntary, predictable response to stimulus
reflex
nerous tissue support cells
line cavities of the brain and spinal cord
circulate cerebrospinal fluid
(glial cells that help circulate CSF)
ependymal cells
protein on postsynaptic membrane that binds neurotransmitter
neurotransmitter receptor
when membrane potential returns to resting values
repolarization
part of a neuron that sends incoming signals toward cell body
dendrites
structure of most common sensory neuron
unipolar
found completely with the CNS connecting neurons together
interneurons
glial cells that control chemical environment of the brain
astrocytes
ion that enters cell causing depolarization
sodium ion
junction between 2 neurons
synapse
region of any axon where an action potential is initiated
trigger zone
gaps in the myelin sheath along axon
nodes of ranvier
what is the membrane potential at which an action potential is generated
threshhold potential
Threshold potential
Membrane potential at which an action
potential is generated
Stimuli from other neurons sum to bring
membrane to threshold
neuron with many extensions from cell body
multipolar neuron
collection of neuronal cell bodies located within the PNS
ganglion
part of the ANS that takes care of housekeeping activities
parasympathetic nervous system
contains vital centers for breathing, heart rate and blood pressure
medulla oblongata
The lowest part of the brain stem
Merges into the spinal cord (has tracts)
Contains important control centers
Heart rate control
Blood pressure regulation
Breathing (respiratory centers – set basic
rate and depth of breathing)
Swallowing & Vomiting
location of cell bodies of motor neurons that innervate skeletal muscle
anterior horn
connective tissue that surrounds a nerve
epineurium
collection of nerve roots that hangs from the inferior spinal cord
cauda equina
coordinates skeletal muscle activity; balance and coordination
cerebellum
bundle of axons found in the CNS
tract
type of fiber located in anterior roots
motor fiber
space between arachnoid and pia mater
subarachnoid space
formed when posterior and anterior roots merge
spinal nerve
region of the brain that interprets most body sensations
parietal lobe
Primary somatic sensory area
Receives and interprets impulses from the
body’s sensory receptors
Speech/language region
helps regulate body temperature and water balance
hypothalamus
Under the thalamus
**important autonomic
nervous system center
**Helps regulate body
temperature
**Controls water
balance
**Regulates
metabolism
**Important part of the
limbic system (emotions)
** Regulates secretions of
hormones from pituitary
gland
type of fiber located within the posterior roots
sensory fiber
part of the ANS used in emergencies and during exercise
sympathetic nervous system
tracts that carry sensory information to brain
ascending tracts
bundle of axons found in the peripheral nervous system
nerves
Neuron fibers are bundled by
connective tissue
* Endoneurium surrounds
each fiber
* Groups of fibers are bound
into fascicles by perineurium
* Fascicles are bound together
by epineurium
Label images
Dendrites
Axon hillock
Cell body/soma
Nucleus
Schwann cells
Node of ranvier
Axon terminals
Nucleus
Cell body
Axon hillock
Schwann cell
Axon terminal
Pia mater
Longitudinal fissure
Longitudinal fissure
Cerebral cortex
Transverse fissure
Lateral ventricle
Lateral ventricle
Third ventricle
Fourth ventricle
what does this do?
Frontal lobe, primary motor area
voluntary control of skeletal muscles
sends impulses to skeletal muscles
Broca’s area- motor speech
involved in our ability to speak
problem solving; working memory; judgment
language comprehension region
what does this do?
Parietal lobe, primary somatic sensory area.
receives and interprets impulses from the body’s sensory receptors
speech/language region
what does this do?
Temporal lobe, olfaction (smell), hearing
what is a cluster of neuronal cell bodies (somas) located in the peripheral nervous system called
ganglion
Which connective tissue bundles axons into fascicles
Perineurium
what is a sensation of pain from visceral organs that appears to arise from skin
referred pain
Cutaneous and visceral sensory neurons
conduct nerve impulses through same
ascending tracts
Visceral injury usually results in dull pain
that is hard to localize
* Clinicians know that pain felt in certain
somatic regions could be referred from the
viscera
what are the two subdivisions of the autonomic nervous system
Sympathetic nervous system (SNS)
Extraordinary situations (fight or flight)
Exercise, excitement, emergency and
embarrassment
Parasympathetic nervous system (PSNS)
Housekeeping activities (rest and repose)
Digestion, defecation, and diuresis
the system the involve extraordinary situations, exercise, excitement, emergency, and embarra
sympathetic nervous system
system that involves the normal housekeeping activities, digestion, defecation, and diuresis
parasympathetic nervous system
digestive system-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: increases smooth muscle mobility and amount of secretion by glands and relaxes sphincters
SNS: decreases activity and constricts sphincters
lungs-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: constricts bronchioles
SNS: dilates bronchioles
heart-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: decreases rate; slows and steadies
SNS: increases rate and force
blood vessels-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: no effect on most blood vessels
SNS: constricts blood vessels in viscera and skin; increases blood pressure
glands-salivary, lacrimal, gastric-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: stimulates increases production of saliva, tears,
SNS: inhibits; result is dry mouth and dry eyes
eye-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS stimulates constrictor muscles; constricts pupils
SNS: stimulates dilator muscles; dilates pupils
sweat glands of skin-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: no effect
SNS; stimulates to produce perspiration
arrector pili muscles attached to hair follicles
PSNS; no effect
SNS; stimulates; produces good bumps
what is humoral stimulation
refers to the control of hormone release in response to changes in extracellular fluids such as blood or the ion concentration in the blood
ions or nutrients cause the release of hormones
what secretes epinephrine the flight or flight hormone
adrenal medulla
stimulates increases in blood sugar
increases blood flow to skeletal muscles
increases metabolic rate in response to short term stress
what simulates milk production
(prolactin-stimulates milk production)PRL
affect non-endocrine targets
what produces sperm, secretes androgens, testosterone
testes, gonads
a hormone secreted by the thyroid that has the effect of lowering blood calcium.
calcitonin
chemical messenger of the endocrine system uses, what actions do they accomplish
hormone
regulation of metabolism
maintenance of homeostasis
mobilization of body defenses
reproduction
endocrine gland secretes hormone until ?
it receives feedback signaling the gland to inhibit hormone secretion.
it uses a negative feedback loop that is a homeostatic mechanism
what stimuli that activate endocrine glands: 3 kinds and how do they work
hormonal stimulation-most common stimulus. endocrine organs are activated by other hormones
humoral stimulation -changing blood levels of certain ions and nutrients stimulate hormone release examples: calcium (parathyroid hormone & calcitonin) or glucose (insulin & glucagon)
neural- stimulate the nerve and impulses stimulate hormone release
ex: release of epinephrine (& some norepinephrine) by the adrenal medulla
humoral stimulation
changing blood levels of certain ions and nutrients stimulate hormone release
ex: calcium parathyroid hormone
what is it called when there is hyposecretion of parathyroid hormone
tetany
hyposecretion of parathyroid hormone (PTH). Insufficient PTH leads to reduced blood calcium ion levels, which in turn cause overactivity in neurons that control muscles. Tetany refers to the resulting uncontrollable muscle spasms.
affect non-endocrine targets that stimulates growth, especially in bones and muscles
growth hormone
what is it called when there is hyposecretion of antidiuretic hormone
diabetes insipidus
hyposecretion of antidiuretic hormone (ADH). Without ADH, the kidney tubules are unable to reabsorb enough water, leading to excess urine production and continual thirst.
what is it called when there is hyposecretion of insulin
diabetes mellitus
hyposecretion of insulin. Without adequate insulin production from the pancreas, blood glucose levels rise dramatically. Affected individuals experience excessive urine production and thirst as well as hunger and weight loss.
what is it called when there is hypersecretion of thyroid hormone
graves’ disease
hypersecretion of thyroid hormone (TH). Graves’ disease is a form of hyperthyroidism in which overproduction of TH causes increased metabolic rate, hyperactivity, weight loss, and a bulging of the eyes anteriorly.
Hormones act through what two different cell mechanisms
direct gene activation or second-messenger systems
Hormones that stimulate other endocrine glands to release hormones
tropic hormones
(Thyroid-stimulated hormone - stimulates thyroid gland to secrete thyroid hormone)TSH
(adrenocorticotropic hormone-stimulates the adrenal cortex to secrete glucocorticoids like cortisol) ACTH
(follicle-stimulating hormone-stimulates the production of sperm and eggs) FSH
(luteinizing hormone-stimulates the testes and ovaries) LH
Located posterior to the third ventricle of the brain around midbrain. secretes melatonin which is
involved in biological rhythms
pineal gland
Gonads
Ovaries: produce ova, secretes steroid hormones
estrogens-stimulate development and maintenance of female secondary sex characteristics
progesterone-promotes growth uterine lining (endometrium)
Testes: produce sperm and secrete androgens
testosterone- stimulates development and maintenance of male secondary sex characteristics
supports formation of sperm cells
Eye
70 % of all sensory receptors
1million nerve fibers (axons)
most of the eye is enclosed in a bony orbit
cushion of fat surrounds most of the eye
membrane that lines eyelids and covers the outer surface of eye
secretes mucus to lubricate eye and keep it most
conjunctiva-membrane that lines the eyelids
includes blood vessels
lacrimal gland and ducts
functions: protects, moistens, and lubricates the eye
empties into nasal cavity
secretions contain: dilute salt solution, mucus, antibodies, lysozyme-destroys bacteria
lacrimal apparatus
Lacrimal gland-produces lacrimal fluid tears, situated on lateral aspect of each eye
lacrimal canaliculi-drain lacrimal fluid from eyes medially
lacrimal sac-provides passage of lacrimal fluid towards nasal cavity
nasolacrimal duct-empties lacrimal fluid into the nasal cavity
six skeletal muscles produce eye movements
originate on wall of orbit and insert into outer surface of eye
external eye muscles
fluids that fill the interior of eyeball
humors
smooth muscle; connected to lens by suspensory ligments
ciliary body
regulates amount of light entering eye, pigmented layer that give eye color
iris
pupil rounded opening in the iris
wall of eyeball consists of 3 layers
outside fibrous layer
sclera -white of the eye, connective tissue layer
cornea- transparent, central anterior portion, allows light to pass through, repairs itself easily, only human tissue that can be transplanted without fear of rejection
choroid- middle , vascular layer-blood rich nutritive layer in the posterior of eye, pigment prevents light from scattering
retina-inside , sensory layer contains 2 layers
outer pigmented layer absorbs light and prevents it from scattering
inner neural layer that contains receptor cells (photoreceptors) rods & cones
What are Photoreceptors that absorb light and send signal to
bipolar neurons then ganglion cells?
* Signals leave retina through the optic nerve
* Optic disc (blind spot) is where the optic nerve
leaves the eyeball
* No photoreceptor cells are at the optic disc, or
blind spot
* Cannot see images focused on the optic disc
Photoreceptor cells
* Rods
* Most are found toward the edges of the retina
* Allow vision in dim light and peripheral vision
* All perception is in gray tones
Photoreceptor cells
* Cones
* Allow for detailed color vision
* Densest in the center of the retina
* Fovea centralis – lateral to blind spot
* Area of the retina with only cones
* Region of sharpest vision (visual acuity
Cone sensitivity
Three types of cones
* Red
* Green
* Blue
* Different cones are sensitive
to different wavelengths
* Color blindness is the result
of the lack of one cone type
Biconvex crystal-like structure
* Focuses image on retina
* Held in place by ciliary zonule (suspensory
ligament) attached to the ciliary body
lens
Lens divides the eye into two chambers
1. Anterior segment
* Anterior to the lens
* Contains aqueous humor
* Helps maintain intraocular pressure
* Provides nutrients for the lens and cornea
- Posterior segment
* Posterior to the lens
* Contains vitreous humor
* Gel-like substance posterior to the lens
* Prevents the eye from collapsing
* Helps maintain intraocular pressure
physiology of vision
Light must be focused to a point on the retina
for optimal vision
* Light is bent, or refracted, by the cornea,
aqueous humor, lens, and vitreous humor
* The eye is set for distance vision (>20ft away)
* Accommodation — the lens must change shape
to focus on closer objects (< 20ft away)
Image formed on the retina is a real image
* Real images are:
* Reversed from left to right
* Upside down
* Smaller than the object
The pathway of light
through the eye:
1. Cornea
2. Aqueous humor
3. Through pupil
4. Aqueous humor
5. Lens
6. Vitreous humor
7. Retina
Location where the optic nerves cross
* Fibers from the medial side of each eye cross
over to the opposite side of the brain
optic chiasma
Contain fibers from the lateral side of the eye
on the same side and the medial side of the
opposite eye
optic tracts
The pathway of nerve impulses from the
retina of the eye into the brain:
- Optic nerve
- Optic chiasm
- Optic tract
- Thalamus
- Optic radiation
- Visual cortex in occipital lobe of brain
visual fields
Visual field – what an eye “sees”
* Slightly different visual field for each eye
* Visual fields overlap
* Inputs from both eyes to each optic cortex
provide for depth perception
the ear is divided into three areas
External (outer) ear
2. Middle ear (tympanic cavity)
3. Inner ear (bony labyrinth
Involved in hearing only
* Structures of the external ear
* Auricle (pinna)
* External acoustic meatus
(auditory canal)
* In the temporal bone
* Lined with skin and
ceruminous glands
* Ends at the tympanic
membrane (eardrum)
external ear tympanic cavity
Air-filled cavity within the
temporal bone
* Involved only in the sense
of hearing
* Located between tympanic
membrane and oval and
round windows
middle ear tympanic cavity
Includes sense organs for
hearing and balance
* Maze of bony chambers within
the temporal bone that forms
the:
* Cochlea
* Vestibule
* Semicircular canals
inner ear and bony labyrinth
Membranous labyrinth series of sac and tubes that
conform to shape of bony labyrinth
* Fluids
* Perilymph – between bony and membranous labyrinth
* Endolymph - within membranous labyrinth
Equilibrium receptors of the inner ear are called
the ?
* It has two functional parts:
1. Static equilibrium
2. Dynamic equilibrium
vestibular apparatus
Receptors in the vestibule
* Report on the position of the head (static equil)
* Send information via the vestibular nerve
maculae
In the ampulla of each semicircular canal
* Receptors that respond to angular or rotary
movements (dynamic equilibrium)
crista ampullaris
cochlear duct
Vestibular membrane – separates cochlear duct
from scali vestibule
* Basilar membrane – separates cochlear duct from
scali tympani
Located within the cochlear duct
* Receptors hair cells on the basilar membrane
* Gel-like tectorial membrane is capable of
bending hair cells
* Cochlear nerve attached to hair cells transmits
nerve impulses to auditory cortex on temporal
lobe
spiral organ of corti
mechanism of hearing
Vibrations from sound waves move tectorial
membrane
* Hair cells are bent by the membrane
* An action potential starts in the cochlear nerve
* Impulse travels to the temporal lobe
High-pitched sounds disturb the short, stiff fibers
of the basilar membrane
* Hair cells close to the oval window are stimulated
* Low-pitched sounds disturb the long, floppy
fibers of the basilar membrane
* Hair cells closer to apex are stimulated
- receptors respond to sugars, saccharine,
some amino acids?
2 ? receptors respond to H ions or acids
3 ? receptors respond to alkaloids
4 ? receptors respond to metal ions
5 ? receptors respond to the amino acid
glutamate or the beefy taste of mea
1.Sweet receptors respond to sugars, saccharine,
some amino acids
2 Sour receptors respond to H ions or acids
3Bitter receptors respond to alkaloids
4 Salty receptors respond to metal ions
5 Umami receptors respond to the amino acid
glutamate or the beefy taste of mea
receptor cells
* Possess ____ hairs
(long microvilli)
* Hairs are stimulated by
chemicals dissolved in saliva
gustatory cells
possess gustatory hairs
Impulses are carried to the gustatory complex
by several cranial nerves because taste buds
are found in different areas
Taste buds are replaced
frequently by
basal cells
Projections on surface of tongue are called
Papillae – projections on surface of tongue
* Filiform papillae—sharp with no taste buds
* Fungiform papillae—rounded with taste buds
* Circumvallate papillae—large papillae with taste buds
taste buds are primarily found on the sides of papillae
taste buds house the receptor organs
* Locations of taste buds?
- Locations of taste buds
- Most are on the tongue
- Soft palate
- Cheeks
Olfactory receptors are in what area and what do they do
Olfactory receptors are in roof of nasal cavity
- Olfactory receptors cells (neurons) with long cilia
known as olfactory hairs detect chemicals - Chemicals must be dissolved in mucus for
detection by chemoreceptors called olfactory
receptors - Impulses are transmitted carries on the olfactory
nerve - Interpretation of smells is made in the cerebral
cortex
Taste and smell use what receptors?
Both senses use chemoreceptors
- Stimulated by chemicals in solution
- Taste has at least four types of receptors
- Smell can differentiate a large range of chemicals
- Both senses complement each other and
respond to many of the same stimuli
spinal cord anatomy: spinal nerves leave at the level of each vertebra
Dorsal (posterior) roots
Sensory fibers
Cell bodies of these neurons found in the
dorsal root ganglia
Ventral (anterior) roots
Contains motor fibers
Cell bodies of these motor neurons are found in anterior horn
what are PNS
Structure: multipolar neurons
Cell body within PNS
Carry impulses from the PNS to viscera,
muscles, or glands
Motor (efferent) neurons
what are Found in neural pathways within the central
nervous system
Structure: multipolar neurons
Some cell bodies in nuclei of CNS
Connect neurons
Interneurons (association neurons)
Sensory receptor
what do different ones do?
Sensory receptor
Specialized dendritic endings, cell or complex
structures
Provide information about internal and
external environment
Sensory receptors in skin and viscera –
temperature, touch, pain, pressure
Proprioceptors
Detect stretch or tension in muscles,
tendons, joints
Gives information on body position
Portion of Schwann cell
that contains most of the
cytoplasm and nucleus
neurilemma
only on myelinated axons
