Chapter 7,8,9 Flashcards

1
Q

Which component of the endocrine system produces the body’s major metabolic hormone? and what two hormones?

A

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

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2
Q

What has four small masses on posterior of the thyroid gland? what hormone does this gland secrete?

A

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

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3
Q

what secretes insulin and glucagon to regulate blood glucose levels and where is it located

A

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

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4
Q

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

A

anterior pituitary gland- glandular tissue: secretes 6 hormones
posterior pituitary-nervous tissue secretes 2 hormones

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5
Q

How are blood levels of most hormones kept within a narrow range ?

A

negative feedback: which is a homeostatic mechanism. endocrine gland secretes hormone until it receives a feedback signaling the gland to inhibit hormone secretion

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6
Q

what involves nerve fibers directly stimulating hormone release from an endocrine gland?

A

neural stimuli,

most endocrine glands respond to hormonal or humoral stimuli

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7
Q

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.

A

second-messenger system
They are used by protein, peptide, and amine hormones which are water soluble. so must bind to receptor

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8
Q

this results in synthesis of new proteins, used by steroid hormones. they are lipid soluble

A

direct gene activation
all steroids use gene activation

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9
Q

what releases insulin in response to high blood glucose levels?

A

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

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10
Q

what releases glucagon in response to low blood glucose levels produced in pancreatic islets

A

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

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11
Q

the hormone that simulates the contraction of smooth muscle in the uterus is

A

oxytocin, oxytocin also initiates milk ejection during lactation

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12
Q

what triggers ovulation and ovarian production of estrogens and progesterone in women?

A

luteinizing hormone, this stimulates testosterone production in men

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13
Q

what promotes maturation of ovarian follicles and stimulates production of eggs and sperm

A

follicle stimulating hormone, in men it stimulates sperm production

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14
Q

the posterior pituitary stores and releases which hormones?

A

(oxytocin-stimulates uterine contractions)OT
(antidiuretic hormrone, produced by the hypothalamic neurons- stimulates water retention by the kidneys) ADH

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15
Q

what does the anterior pituitary gland produce and release?

A

(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

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16
Q

what hormone produced by the placenta loosens pelvic ligaments prior to birth

A

relaxin

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17
Q

what triggers ovulation of an egg from the ovary and stimulates testosterone production in the testes

A

(luteinizing hormone-stimulates the testes and ovaries) LH

an anterior pituitary hormone

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18
Q

where are the parathyroid glands located

A

posterior surface of the thyroid gland, they release parathyroid hormone in response to low blood calcium ion levels

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19
Q

where is the thymus located and what hormone does it secrete for what?

A

anterior to heart and posterior to the sternum
largest in infants and children
Secretes thymosin-involved with the development of the immune system

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20
Q

ON the the superior surface of each kidney (suprarenal glands)
has 2 regions

A

Adrenal glands
(adrenal cortex-outer 80-90% of gland)
(adrenal medulla- inner 10-20% of gland, nervous tissue

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21
Q

what secretes nonhormonal substances into ducts that empty onto a membrane surface

A

exocrine glands, such as salivary glands and sweat glands

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22
Q

what are the gonadotropic hormones

A

luteinizing hormone and follicle stimulating hormone

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23
Q

what causes acromegaly a condition in which the bones of the face, hands and feet enlarge and widen

A

hypersecretion of growth hormone in an adult
what is it called when there is hyposecretion of growth hormone, gigantism

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24
Q

Has three layers that secrete different steroid hormones in region of adrenal glands

A

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

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25
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
26
where is thyroid gland located
in the anterior neck just inferior to the voice box
27
a hormone that works by direct gene activation must be
lipid soluble
28
which hormone is the most important regulator of blood calcium ion levels
parathyroid hormone
29
a current that is continuously regenerated along the length of the axon and does not die out
action potential
30
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
31
the middle layer of the meninges, had weblike extensions attach to the inner layer, the pia mater
arachnoid mater
32
nervous tissue support cells abundant, start shaped cells form barrier btwn capillaries and neurons control the chemical environment of the brain
astrocytes
33
what is a stimulus
a change in the environment
34
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
35
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
36
what gathers information and monitors changes, stimuli occuring inside and outside the body
sensory input
37
what is the process and interpret sensory input and decide if action is needed
integration
38
what response to integrated stimuli and activate muscles to contract or glands secrete
motor output
39
PNS peripheral 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
40
what is the region that initiates action potential (impulses)
trigger zone
41
what is a neurons ability to respond to stimuli and convert it into an action potential (nerve impulse)
irritability
42
what is a neurons ability to transmit an impulse and send signal to next cell
conductivity
43
what part of nervous system monitors changes (stimuli) occurring in side and outside the body gathers information
sensory input (on afferent pathway)
44
what part of nervous system responds to integrated stimuli and activates muscle or glands
motor output to an effector like skeletal muscle
45
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
46
what is central nervous system composed of
brain and spinal cord
47
what is the peripheral nervous system composed of
cranial nerves and spinal nerves
48
in the sensory division what carries information from peripheral Nervous system to the central nervous system
nerve fibers
49
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
50
what are the effectors of the autonomic nervous system?
smooth muscle, cardiac muscle, and glands
51
what does nervous system consists of
neurons and neuroglia (6types of glial cells) oligodendrocytes schwann cells ependymal cells astrocytes microglia satellite cells
52
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
53
what is another name for nerve impulses?
action potentials
54
what is most abundant glial cell? star shaped cells touch capillaries and neuron
astrocytes
55
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
56
nervous tissue support cells phagocytose bacterial cells and cellular debris in the CNS
microglia
57
what lines the cavities of the brain and the central canal of the spinal cord and circulate cerebrospinal fluid
ependymal cells
58
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
59
nervous tissue support cells that protect neuron cell bodies in ganglia of the peripheral nervous system
satellite cells
60
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
61
cells specialized to transmit nerve impulses or action potential. the 3 major regions of have a cell body, dendrites, axon
neurons=nerve cells
62
what is another name for cell body
soma
63
anatomy of cell body
nucleus large nucleolus nissl substance neurofibrils
64
what is the specialized rough endoplasmic reticulum of the cell body
nissl substance
65
what helps maintain cell shape of cell body
neurofibrils
66
what is short highly branched cytoplasmic extensions that conduct signoals toward the cell body
dendrites
67
what only has one neuron, arises from the axon hillock and may have branches, collaterals and a trigger zone
axon
68
what contains vesicles with neurotransmitters
axon terminals
69
what is gap separated from one neuron to next
synaptic cleft, gap btwn adjacent neurons
70
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
71
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
72
what are the two control systems in the body
nervous system and endocrine system
73
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
74
what are some major hormonal actions
regulation of metabolism maintenance of homeostasis mobilzation of body defenses growth and development reproduction
75
what are ductless glands; produce hormones and secrete hormones into the blood, and have a rich blood supply, formed from epithelial tissue
endocrine glands
76
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
77
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
78
what are hormones made from proteins, peptides, amines
amino acids
79
what are the hormones made from cholesterol
steroids
80
what are the hormones made from lipids secreted by virtually all body cells;
prostaglandins
81
what are the mechanisms of hormones action. what activates genes so proteins are synthesized?
steroid hormones
82
What is irritability
The ability to respond to stimuli and convert it into an action potential
83
What is conductivity
Ability to transmit an impulse and send signal to next cell
84
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)
85
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
86
Resting membrane potential
The voltage difference at resting varies with cell type -40 to -90 mV
87
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
88
DNA, RBA, proteins contribute to resting membrane potential because
Negatively charged molecules
89
What contributes to membrane potential in resting neuron
90
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
91
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
92
What is an action potential
Rapid sequence of depolarization and repolarization
93
Resting potential of a neuron
-70
94
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
95
What is the peak voltage of action potential for a neuron
+10mV
96
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
97
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
98
AP appears to jump from node of ranvier to node of ranvier
saltatory conduction, relatively fast 120m/sec on myelinated axon
99
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.
100
conduction on unmyelinated axon
action potential travels along entire plasma membrane relatively slow .5m/sec slow for action potential
101
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
102
post synaptic neuron transmits to?
can be dendrites or cell body, covered with synapses
103
what is junction btwn 2 neurons
synapse
104
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 1. 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
105
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
106
where are neurotransmitters stored
within synaptic vesicles
107
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
108
refexes that stimulate the skeletal muscles, example pulling hand away from hot object
somatic reflexes
109
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
110
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
111
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
112
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
113
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
114
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
115
double-layered external covering separates to form dural sinuses filled with venus blood
dura mater
116
middle layer web-like
arachnoid mater
117
clings to surface of brain and spinal cord contain superficial blood vessels
pia mater
118
space between arachnoid and pia mater filled with cerebrospinal fluid
subarachnoid space
119
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
120
how many layers is the dura mater in the spinal cord
1
121
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
122
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
123
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)
124
what structure makes cerebrospinal fluid
choroid plexus
125
includes the least permeable capillaries of the body excludes many potentially harmful substances useless as a barrier against some substances
blood-brain barrier
126
what are some useless as a barrier against some substances
fats and fat soluble molecules respiratory gases (co2 & o2) alcohol nicotine anesthesia
127
what are the 4 major portions for the brain
 4 major portions  Cerebrum (cerebral hemispheres), diencephalon, brain stem, cerebellum
128
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
129
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
130
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
131
regions of gray matter buried within the white matter of cerebrum
basal nuclei
132
what is the thin layer of gray matter on the surface of the brain called
cerebral cortex
133
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)
134
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
135
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
136
vision area in the cerebrum, everything involved with vision
occipital lobe
137
in the cerebrum the fiber tracts-bundles of myelinated axons, deep to grey matter
white matter
138
what are bundles of myelinated axons
fiber tracts
139
what is the largest fiber tract that connects hemispheres of the cerebrum
corpus callosum
140
regulate skeletal muscle movements (starting and stopping activity
basal nuclei
141
what sits on top of the brain stem, enclosed by the cerebral hemispheres, main parts thalamus and hypothalamus deep to 2 cerebral hemispheres
diencephalon
142
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
143
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
144
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
145
what attaches to the spinal cord, and has midbrain, pons, medulla oblongata
parts of brain stem
146
mostly composed of tracts of nerve fibers; reflex centers for vision and hearing in the brain stem
midbrain
147
mostly fiber tracts; modifies activity of respiratory centers in the medulla
pons
148
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
149
coordinates skeletal muscle activity; helps maintain posture; balance and equilibrium
cerebellum
150
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
151
how many pairs of spinal nerves are there in the spinal cord
31pairs
152
what is a collection of spinal roots or cluster of nerve roots at the inferior end of the spinal cord
cauda equina
153
a deep groove; on the front surface of spine; anterior on the midline
anterior median fissure
154
shallow groove on the midline on the posterior spinal cord
posterior median sulcus
155
at what vertebral level does the spinal cord end
L1
156
which type of matter is on the exterior of spinal cord
exterior white matter
157
sensory fibers; cell bodies of these neurons found in the dorsal root ganglia
dorsal (posterior) roots
158
contains motor fibers; cell bodies of these motor neurons are found in the anterior horn
ventral (anterior) roots
159
what type of fiber is located in the posterior roots
sensory fibers
160
what conducts signal away from cell body toward axon terminal
axon
161
when membrane potential becomes more positive or less negative
depolarization
162
what is the end of axon called
axon terminal
163
what is the specialized RER found in a neuron
nissl substance
164
what are the phagocytic cells found in CNS called
microglia
165
what produce myelin sheath in CNS
oligodendrocytes
166
brain and spinal cord
central nervous system
167
form myelin sheath in PNS
schwann cells
168
conduction of an action potential in a myelinated axon
saltatory conduction
169
rapid, involuntary, predictable response to stimulus
reflex
170
nerous tissue support cells line cavities of the brain and spinal cord circulate cerebrospinal fluid (glial cells that help circulate CSF)
ependymal cells
171
protein on postsynaptic membrane that binds neurotransmitter
neurotransmitter receptor
172
when membrane potential returns to resting values
repolarization
173
part of a neuron that sends incoming signals toward cell body
dendrites
174
structure of most common sensory neuron
unipolar
175
found completely with the CNS connecting neurons together
interneurons
176
glial cells that control chemical environment of the brain
astrocytes
177
ion that enters cell causing depolarization
sodium ion
178
junction between 2 neurons
synapse
179
region of any axon where an action potential is initiated
trigger zone
180
gaps in the myelin sheath along axon
nodes of ranvier
181
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
182
neuron with many extensions from cell body
multipolar neuron
183
collection of neuronal cell bodies located within the PNS
ganglion
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part of the ANS that takes care of housekeeping activities
parasympathetic nervous system
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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
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location of cell bodies of motor neurons that innervate skeletal muscle
anterior horn
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connective tissue that surrounds a nerve
epineurium
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collection of nerve roots that hangs from the inferior spinal cord
cauda equina
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coordinates skeletal muscle activity; balance and coordination
cerebellum
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bundle of axons found in the CNS
tract
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type of fiber located in anterior roots
motor fiber
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space between arachnoid and pia mater
subarachnoid space
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formed when posterior and anterior roots merge
spinal nerve
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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
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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
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type of fiber located within the posterior roots
sensory fiber
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part of the ANS used in emergencies and during exercise
sympathetic nervous system
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tracts that carry sensory information to brain
ascending tracts
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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
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Label images
Dendrites Axon hillock Cell body/soma Nucleus Schwann cells Node of ranvier Axon terminals
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Nucleus
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Cell body
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Axon hillock
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Schwann cell
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Axon terminal
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Pia mater
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Longitudinal fissure
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Longitudinal fissure
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Cerebral cortex
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Transverse fissure
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Lateral ventricle
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Lateral ventricle
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Third ventricle
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Fourth ventricle
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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
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what does this do?
Parietal lobe, primary somatic sensory area. receives and interprets impulses from the body's sensory receptors speech/language region
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what does this do?
Temporal lobe, olfaction (smell), hearing
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what is a cluster of neuronal cell bodies (somas) located in the peripheral nervous system called
ganglion
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Which connective tissue bundles axons into fascicles
Perineurium
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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
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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
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the system the involve extraordinary situations, exercise, excitement, emergency, and embarra
sympathetic nervous system
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system that involves the normal housekeeping activities, digestion, defecation, and diuresis
parasympathetic nervous system
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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
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lungs-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: constricts bronchioles SNS: dilates bronchioles
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heart-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: decreases rate; slows and steadies SNS: increases rate and force
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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
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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
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eye-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS stimulates constrictor muscles; constricts pupils SNS: stimulates dilator muscles; dilates pupils
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sweat glands of skin-effects of sympathetic and parasympathetic divisions of the autonomic nervous system
PSNS: no effect SNS; stimulates to produce perspiration
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arrector pili muscles attached to hair follicles
PSNS; no effect SNS; stimulates; produces good bumps
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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
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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
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what simulates milk production
(prolactin-stimulates milk production)PRL affect non-endocrine targets
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what produces sperm, secretes androgens, testosterone
testes, gonads
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a hormone secreted by the thyroid that has the effect of lowering blood calcium.
calcitonin
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chemical messenger of the endocrine system uses, what actions do they accomplish
hormone regulation of metabolism maintenance of homeostasis mobilization of body defenses reproduction
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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
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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
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humoral stimulation
changing blood levels of certain ions and nutrients stimulate hormone release ex: calcium parathyroid hormone
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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.
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affect non-endocrine targets that stimulates growth, especially in bones and muscles
growth hormone
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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.
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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.
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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.
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Hormones act through what two different cell mechanisms
direct gene activation or second-messenger systems
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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
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Located posterior to the third ventricle of the brain around midbrain. secretes melatonin which is involved in biological rhythms
pineal gland
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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
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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
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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
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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
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six skeletal muscles produce eye movements originate on wall of orbit and insert into outer surface of eye
external eye muscles
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fluids that fill the interior of eyeball
humors
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smooth muscle; connected to lens by suspensory ligments
ciliary body
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regulates amount of light entering eye, pigmented layer that give eye color
iris pupil rounded opening in the iris
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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
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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
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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
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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 2. 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
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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)
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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
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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
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Contain fibers from the lateral side of the eye on the same side and the medial side of the opposite eye
optic tracts
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The pathway of nerve impulses from the retina of the eye into the brain:
1. Optic nerve 2. Optic chiasm 3. Optic tract 4. Thalamus 5. Optic radiation 6. Visual cortex in occipital lobe of brain
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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
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the ear is divided into three areas
External (outer) ear 2. Middle ear (tympanic cavity) 3. Inner ear (bony labyrinth
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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
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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
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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
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Equilibrium receptors of the inner ear are called the ? * It has two functional parts: 1. Static equilibrium 2. Dynamic equilibrium
vestibular apparatus
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Receptors in the vestibule * Report on the position of the head (static equil) * Send information via the vestibular nerve
maculae
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In the ampulla of each semicircular canal * Receptors that respond to angular or rotary movements (dynamic equilibrium)
crista ampullaris
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cochlear duct
Vestibular membrane – separates cochlear duct from scali vestibule * Basilar membrane – separates cochlear duct from scali tympani
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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
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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
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1. 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
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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
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Taste buds are replaced frequently by
basal cells
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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
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taste buds house the receptor organs * Locations of taste buds?
* Locations of taste buds * Most are on the tongue * Soft palate * Cheeks
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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
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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
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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
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what are PNS  Structure: multipolar neurons  Cell body within PNS  Carry impulses from the PNS to viscera, muscles, or glands
Motor (efferent) neurons
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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)
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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
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 Portion of Schwann cell that contains most of the cytoplasm and nucleus
neurilemma only on myelinated axons