Exam 1 Flashcards
What connects nerves to their effectors?
Peripheral motor endings
Where are motor endings found? What do they do?
Peripheral Nervous System (PNS)
They release neurotransmitters
What type of movement does innervation of skeletal muscles create? From what part of the PNS?
Voluntary Movement
Somatic Nervous System
Innervation of skeletal muscles: Where is Ach released?
Released at a synapse called the neuromuscular junction (NMJ)
Innervation of Viceral Muscles and glands from what part of the PNS?
Autonomic NS
Innervation of Visceral Muscles and Glands: What is released and where?
Ach or Norepinephrine at varicosities
What are the three levels of motor control?
Segmental, Projection, and Precommand
The Segmental Level of Motor Control
-Spinal cord segment level
-motor neurons in ventral horn and interneurons
-final outputs for muscle movement; reflex circuits
–segmental level important for pattern movement
area of the brain involved in The Segmental Level of Motor Control
-motor neurons in ventral horn and interneurons
The projection level
-motor cortex (+axons to spinal cord)
-“upper motor neurons” that command voluntary movements
area of the brain involved in the The projection level
-motor cortex (+axons to spinal cord)
the precommand level
-cerebellum and basal nuclei
–influence motor cortex and help refine movements
Reflex activity are…
The reflex arc enables…
quick movements
rapid and predictable responses
Reflexes are…
involuntary, stereotyped responses to stimulus (movements)
Components of a reflex arc
-Pathway of neurons that are responsible for the movement
Receptor-> afferent-> integration center w/ interneurons-> motor efferent-> effector muscle
What are spinal reflexes?
somatic reflexes mediated by the spinal cord
(can occur without direct involvement of higher brain areas)
Stretch reflex
External stimulus creates the stretch- the reflex is contraction
Goal of the stretch reflex
keep posture with external stimulus
-when muscle X is stretched by something it reflexively contracts and at the same time motor neurons antagonist to muscle X (muscle Y) are inhibited
ARC steps with stretch reflex
- Muscle spindle detects stretch
- spindle afferent excite muscle X motor neuron and interneuron (interneuron inhibits antagonist motor neurons)
What are the effectors of the somatic nervous system?
skeletal muscles
What are the effectors of the autonomic nervous system?
smooth muscle, heart, glands
Where are the cell bodies of neurons in the somatic N.S.
where do their axons extend?
spinal cord
to the skeletal muscle they innervate
where do the axons of neurons in the somatic NS extend to?
the skeletal muscles they innervate
The ANS consists of (in terms of efferent pathways and ganglia)
A two neuron chain
The 1st neuron: preganglionic; its soma in the CNS, its axon terminates in a ganglion
The 2nd neuron: postganglionic neuron; its soma in the ganglion, its axon terminates on effector (w varicosities)
1st neuron in the ANS
(where is its soma, where does its axons terminate, pre or postganglionic)
preganglionic; its soma in the CNS, its axon terminates in a ganglion
2nd neuron in the ANS
postganglionic neuron; its soma in the ganglion, its axon terminates on effector (w varicosities)
what neurotransmitter is released by somatic motor neurons
acetylcholine
What do the neurotransmitters in the ANS within ganglia release? what does it do?
releases ACh from preganglionic cell which excites the postganglionic cell
what does acetylcholine do?
excites skeletal muscle
What do the neurotransmitters in the ANS releases at effector?
the preganglionic releases EITHER ACh or NE which may excite or inhibit effector
What are the two divisions of the ANS
parasympathetic and sympathetic divisions
Both divisions of the ANS usually serve the same visceral organs, but….
cause opposite effects
the parasympathetic division is manly known to
be lower energy spending
“rest and digest”
the sympathetic division is mainly known two
govern
“fight or flight” to threat
sympathetic and parasympathetic divisions differ in anatomy..
site and origin in the CNS and location of ganglia (therefore axon length)
Long preganglionic parasympathetic fibers originate in the?
Craniosacral CNS
preganglionic axons extend…
From CNS almost all the way to terminal ganglia at or near effector
cranial part of parasympathetic division…
sends preganglionic axons by way of cranial nerves, especially by the vagus nerve (CN 10)
sacral part of parasympathetic divisionn sends axons…
sends axon in nerves to digestive, urinary, and reproductive organs in lower abdomen
short preganglionic sympathetic fibers originate in the…
thoracolumbar CNS
in addition to innervating visceral organs in internal body cavities, sympathetic neurons exclusively innervate..?
superficial structures such as..
sweat glands, arrector pili, and smooth muscle in blood vessels
sympathetic pregang neurons exit the spinal cord via the..
ventral root
all sympathetic ganglia are located
close to the spinal cord (thus, the postganglionic axons are long)
ACh and NE are the major____ transmitters
ANS
Cholinergenic Receptors include
nicotinic and muscurinic
Nicotinic cholinergic receptors are found
on postganglionic neurons (and on skeletal muscles) and are excitatory
muscarinic receptors occur
on parasympathetic effector cells and may be excitory or inhibitory
there are two classes of adrenergic receptors that
produce either an excitory or inhibitory responses
the para and sym divisions usually produce…
opposite effects
most visceral organs receive…
dual innervation by both ANS divisions
iris dual innervation
Para- Constriction
Sym- Dilation
gastric gland dual innervation
Para- increase secretion
Sym- Decrease secretion
heart dual innervation
Para- Slows heart rate
Sym- Increase heart rate and squeeze more
bronchioles dual innervation
para- constricts
sym- dialates
sympathetic tone throughout the vascular system allows..
the firing of sympathetic neurons to control the diameter of BLOOD VESSELS, regulating systemic blood pressure
parasympathetic tone is usually dominant in the
HEART, DIGESTIVE SYSTEM, and URINARY TRACTS, maintaining normal homeostatic levels of function unless overridden by the sympathetic system during stress
what effect do the ANS divisons show on the genetalia
cooperative effect
the sympathetic system has a unique role in
thermoregulation: sweat glands, arrector pili
vascular- constricts skin blood vessels (it dialates other blood vessels)
kidney/ hormones- renin release
the sympathetic system has a unique role in ther omoregulation by
sweat glands and arrector pili
the sympathetic system has a unique role in the vascular system by
contricting skin blood vessels (usually dialates other blood vessels)
the hypothalumus oversees
ANS activity
what has the most direct influence over autonomic functions
the brain stem
the sympathetic system has a unique role in the kidneys/ hormones by
renin release
what is the main integration center for the ANS
hypothalamus
partial control or voulentary control of the ANS may be possible becuase
biofeedback training may enable a person to alter some invoulentary functions
brain stuctures involved in precommand level
-cerebellum and basal nuclei
the endocrine system is one of the bodys two…
main control systems
endocrinology is the study of
hormones and endocrine organs
hormones are
blood borne chemical messengers
hormone targets include
most cells in the body but the cell must have specific receptors: when hormone binds to the receptor cellular metabolism changes
What happens when a hormone binds to a receptor
cellular metabolism changes
endocrine glands are
examples are?
organs that secrete and make hormones, are ductless
include pituitary, thyroid, adrenal, etc. but many organs have some endocrine function
the chemical structure of a hormone determines
how it acts
most hormones are….
but other hormones are…
Where do lipid soluable steroids come from?
amino-acid based and water soluable
lipid soluable steroids such as those from gonads and adrenal cortex
the chemical structure of a hormone impacts its solubility in water which then impacts
its transport in blood, how long it stays in the body, which receptors it binds to
hormones act through….
second messengers or by activating specific genes
hormones can only influence target cells which are cells that
have receptors for that specific horomone
water soluable hormones use
plasma membrane receptors and second messenger systems
The cyclic AMP singaling mechanism
a) hormone binds receptor (on membrane surface)
b) receptor activates g-protein
c) g-protein activates adenyl cyclase (AC)
d) AC makes cAMP
e) protein kinase adds G (guanine) to a protein (eg. an ion chanel protein)
other signaling mechanisms use
different second messengers or work without second messengers to initate a certian cellular responses
lipid soluable hormones use
intracellular receptors and specific gene activation
direct gene activation occurs when
sterioids or thyroxine binds to intracellular receptors and then activate a segment of DNA , i.e, start transcription (start protein synthesis)
What are the three types of stimuli that cause hormone release?
A) Hormone sythesis and release is regulated
B) Endocrine gland stimuli may be humoral, neutral, or hormonal
C) Feedback control
Endocrine gland stimuli may be
humoral, neutral, or hormonal
stimuli that cause hormone release
critical ions or nutrients (humoral)
+ example
high or low levels of a chemical trigger hormone secretion
EG. low Ca++ PTH release
stimuli that cause hormone release
if autonomic (neural)
axons release neurotransmitters to trigger hormone secretion (E.g sympathetic axons releasing adrenaline)
stimuli that cause hormone release
if one hormone (hormonal)
+ example
one hormone stimulates a gland so secrete another hormone
(e.g TSH-TH)
stimuli that cause hormone release
Feedback control + Exp
1) a hormone in the blood often inhibits subsequent release
(e.g. TH inhibits pituitarys release of TSH
cells respond to a hormone if they have….
receptors for that hormone
target cell response depends on three factors….
blood levels of the hormone
reletive number of target cell receptors
affinity of the the receptor for the hormone
target cells can change their sensitivity to a hormone by
changing the number of receptors
target cells can change their sensitivity to a hormone by changing the number of receptors
UP REGULATION
cell becomes more sensitive by expressing more receptors
target cells can change their sensitivity to a hormone by changing the number of receptors
DOWN REGULATION
cell makes less receptors (so becomes less sensitive)
Half life is
how long before the hormone is excreted or inactivated
Is half life shorter for water soluble hormones or lipid soluable hormones
water soluable hormones
Duration of hormonal activity: do water soluable hormones or steriods act quicker?
Water soluable
Interaction of hormones at target cells include
synergysm and antagonism
Interaction of hormones at target cells
SYNERGISM
when 2 hormones interact on a target cell causing a large effect (eg. cortisol + adrenaline)
Interaction of hormones at target cells
ANTAGONISM
when two hormones oppose each other
(eg. insulin vs glucagon)
the hypothamus controls release of hormones from the
pituitary gland
the pituitary gland is situated in the…. of the skull and is connected to the … by the…
STELLA TURICA…BRAIN…INFUNDIBULUM
What are the two lobes of the pituitary
Anterior Pituitary: several hormones
Posterior Pituitary: two hormones (no true grandular cells
the hypothalamic hypophyseal tract connects
The posterior pituitary and the hypothalamus
Pituitary-Hypothalamic relationships:
Two neurohormones are
Oxytocin and ADH
Pituitary-Hypothalamic relationships:
neurohormones oxytocin S+E
Stim: hypothalamic neuron firing
Effect: uterine contraction, lactation, and bonding
Pituitary-Hypothalamic relationships:
neurohormones ADH S+E
Stim: hypothalamus neuron firing
Effect: vasopressin-kidneys conserve water (less urination), and blood vessels constrict
the hypothalamic hypophyseal portal system connects the
anterior pituitary and hypothalamus
the hypothalamic hypophyseal portal system
6 Hormones (four of which are tropic hormones) are
Growth hormone, prolactin, TSH, ACTH, FSH+LSH
6 Hormones (four of which are tropic hormones)
GROWTH HORMONE
S: GHRH from hypothalamus
E: Growth of muscle and bone
6 Hormones (four of which are tropic hormones)
PROLACTIN
S: PRH from hypothalamus
E: Milk Production
6 Hormones (four of which are tropic hormones)
TSH
S: TRH From hypothamus
E:TH AT THYROID
6 Hormones (four of which are tropic hormones)
ACTH
S: CRH from hypothalamus
E: increase cortisol secretion at adrenal gland
6 Hormones (four of which are tropic hormones)
FSH+LH
S: GnRH from hypothalamus
E: increase secretion of hormones and stimulate gamete production
The thyroid controls
Metabolism
The thyroid hormone is a…
S+E?
two amine hormone with iodine— exists as T3 or T4
S: TSH from anterior pituitary
E: increase metabolic rate of the cell and so effects thermoregulation, digestion, and energy levels
Calcitonin….
S+E
is secreted by C cells of the thyroid, is a peptide hormone that
S: high Ca++ in blood
E: Deposit Ca++ in bone
parathyroid glands are primary regulators of
blood calcium
parathyroid glands are located on the
back of thyroid
Parathyroid secretes parathyroid hormone PTH
S+E
S: Low blood Ca++
E: Cause bone to free up Ca++ from bone and put it into blood
the adrenal glands produce hormones that are involved in
electrolyte balance and the stress response
the adrenal gland consists of two regions
the cortex and the medulla
the adrenal cortex produces
corticosteroids
mineralcorticoids, mostly aldosterone
S:angiotensin 2 (a hormone) and other factors
E: increase sodium retention by kidneys
glucocorticoids, such as cortisol
S: ATCH from the anterior pituitary
E: long term stress reponse + increase in blood glucose
gonadocorticoids are mostly weak…. which are converted to _ and_ in the _
adrogens, tesosterone and estrogen, tissue cells
the adrenal medulla synthesiszes epinephrine and norepinephrine
S: sympathetic neuron firing
E: short term stress response, including increase in heart rate, metabolic rate, and blood sugar
the pineal gland secretes
melatonin
melatonin S+E
S: hypothalamus neuron firing
E: sleepiness
the pancreas, gonands, and most other organs secrete
hormones
the pancreas is a mixed gland that secretes _ and _ gland cells
endocrine and exocrine
alpha pancreas cells produce…. beta cells produce….
alpha- glucagon
beta- insulin
glucagon S+E
S: low blood sugar
E: raise blood sugar by causing liver to convert gulcagon to lots of glucose
insulin S+E
S: High blood sugar
E: lower blood sugar by increasing glucose absorption in many tissues. liver forms glycogen from many glucose
the gonads produce
estrogen, testosterone, and progesterone
the ovaries (gonads) produce
estrogen and progesterone
the testes (gonads) produce
testosterone
Ovaries - Estrogen S+E
S: FSH from anterior pitutitary
E: female reproductive functions
Ovaries- Progesterone
S: LH from anterior pituitary
E: female reproductive funtions
testes- testosterone S+E
S: LH from anterior pituitary
E: male reproductive functions
What are the functions of blood (3)?
Transportation, regulation, protection
Transport functions include delivery of
and transport of
Oxygen
CO2, nutrients/ wastes, hormones
blood regulatory functions include maintaining
body temperature, fluid balance, pH
Protective function include preventing
blood loss, infection
Blood consists of
plasma and formed elements
blood is a specialized connective tissue consisting of
Plasma (extracellular), fluid, and formed elements (cells+cell fragments)
What are the 3 layers when blood is seperated
Erythrocytes (RBCS)
buffy coat- WBCs and platelets
plasma
The blood hematocrit represents the
percentage of whole blood that is RBCs
Physical characteristics and volume of blood
-viscous
-around 5L per person
-slightly basic (7.35-7.45 pH)
Blood Plasma consists of
-water (the solvent)
-solutes: electrolytes and proteins
components of protein in blood plasma
-clotting (e.g. fibrogen)
-antibodies- gamma globulins
-albumins: keep concentration normal
Formed elements of the blood are
-RBCs, Platelets, WBCs
-only WBCs have nuclei
Erythrocytes play a crucial role in
oxygen+CO2 transport and exchange
Erythrocytes (RBCs) shape+ characteristics
-Shape: disc, biconcave, large surface area
-No Nuclei, no mitochondria, no protein synthesis, no DNA
-last around 110 days
-made of membrane, Hb protein, and water
Erythrocytes (RBCs) shape+ characteristics
HEMOGLOBIN Characteristics
-key protein in RBCs
-made of 4 peptides together
-each peptide holds a heme group (with iron)
-Hb can hold 4 O2 molecules
Production of Erythrocytes: hematopoisis and its regulation
1) Stim by erythropoietin EPO hormone secreted by the kidneys when O2 is low
2) EPO stimulates red marrow where…
3) Stem cells give rise to more RBCs (Vitamin B12, folic acid, and iron are needed)
4)RBCs last around 110 days and then are removed/ recycled by the spleen
Erythrocyte disorders include
Anemias and polycythemia
Anemia is…
is caused by…
is low oxygen carying capacity
a) hemorrhage
b) low RBC production (iron deficency, lacking B12,
c) high RBC breakdown (e.g. sickle cell)
Polycythemia
-excess RBC production
caused by oxygen deficiency, genetic mutation, or doping
Role of leukocytes
defending the body
Leukocytes are…
WBCs
-are complete
-small number of them
-body defenses
Granulocytes are..
cells with stained granules in cytoplasm
NEUTROPHILLS EOSINOPHILS AND BASOPHILS
Neutrophills…
-make up the majority of WBCs
-attracted to sites of inflammation
-phagocytose bacteria
eosinophils…
-attack parasitic worms
-too many seen in allergies
basophills are..
-least numerous WBCs
-release histamine and heprin for inflammation
what are the two Agranulocytes
LYMPHOCYTES AND MONOCYTES
lymphocytes
-2nd most common WBCs
-T cells (thymus cells) attack infected cells
-B Cells (bone-developed) become plasma cells which make and release antibody proteins
Monocytes
Become macrophanges when they leave blood
2 Leukocyte disorders
Luekemia- cancer of WBCs
Mononucleosis- many lymphocytes develop to attack virus
Platelets
-are formed elements but not whole cells
-are fragments of magokaryocytes
-key role in homeostasis (stopping bleeds)
-stick to broken blood vessels; become spiky/ sticky to form a plug
Transfusion of whole blood is routine only when
blood loss is substantial, treating thrombocytopenia; most of the time-packed RBCs are used
Blood types: A/B/O groups
depend on presence or abstance of A+B proteins on RBCs (O has no protein, AB has both
Antibodies against foreign proteins are found where (blood)
Plasma
(e.g. if you have type-A blood you have Anti-B antibodies)
What is the universal donor?
Universal recipient?
O (donor)
AB (recipient)
RH factor is another _ protein
RBC
Ionotropic (direct) (fast) receptors include
For ACH (cholinergic)
nicotinic- excitirory
Metabotropic (indirect) (slow) receptors include
excititory or inhibitory
For ACH (choliergic)
muscarinic
For NE (adrengeric)
Alpha receptor
beta 1+2 receptor
ACH Receptors
muscarinic- either excitatory or inhibitory
nicotinic- excitatory
Norepi Receptors
Adrenergic- either excitory or inhibitory
Neurons that release ACH in ANS
Long pregang neuron
short postgang neuron
Short pregang neuron
Neurons that release NorEPI IN ANS
long postgang neuron
axons in parasym
long pregang axon and short postgang axon (both release ACH)
axons in sym
short pregang axon (releases ACH) and long postgang axon (releases NE)
insecticides containing organophosphatess inhibit acytylcholinesterase (which breaks down ACH) which autonomic receptors are stimulated excessivly as a result of this inhibition
Acytylcholine receptors
Case study:
which division of ANS has been primary affeced-
constricted pupils and low heart rate
Parasympathetic
Case study:
under what conditions does parasymp of ANS usually dominate
low body energy “rest and digest”
Case study:
What effects may the insecticide have on the GI system
increase digestion
increase diarrhea
Case Study: Is atropine sulfase an antagonist or agonist drug
AntagonistL Ach being inhibited so atropine is counteracting
