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