Physiology Exam 2 Flashcards
What about veins allows them to accommodate high volumes with little change in pressure.
Large Compliance
What is Venous return?
Venous return is the volume of blood returning to the central venous compartment (i.e., thoracic venae cavae and right atrium) per minute.
What promoted Venous return? High or Low CVP?
Low CVP promotes venous return into the central venous compartment.
What inhibits Venous return? High or Low CVP?
High CVP inhibits venous return into the central venous compartment.
If a 20-year-old and a 60-year-old male had the same body mass, cardiac output, heart rate, and mean arterial pressure, which of the following would characterize the circulatory system in the 60year-old as compared to that in the 20-year-old?
A. The 60-year-old man would have a lower systolic pressure.
B. The 60-year-old man would have a higher diastolic pressure.
C. The 60-year-old man would have a higher cardiac workload.
D. The 60-year-old man has elevated arterial resistance.
C. The 60-year-old man would have a higher cardiac workload.
Which of the following will be seen when both heart rate and stroke volume are increased? A. Increased mean arterial pressure B. Increased central venous pressure C. Increased pulse pressure D. Decreased diastolic pressure
C. Increased pulse pressure
Which of the following is true of the relationship between cardiac output (CO) and central venous pressure (CVP)?
A. Increased CVP increases CO
B. Equal CO to CVP results in increased flow (L/min)
C. Increased CO increases CVP
D. Decreased CVP increases CO
D. Decreased CVP increases CO
Autoregulation of blood flow in organs such as the heart and brain allows:
A. changes in arterial pressure to cause proportional changes in organ blood flow.
B. their oxygen supply to remain stable in spite of fluctuations in arterial pressure.
C. constriction of their arterioles when arterial pressure decreases.
D. neurogenic reflexes to control vascular resistance in those organs.
B. their oxygen supply to remain stable in spite of fluctuations in arterial pressure.
If blood flow to an organ is 100 mL/minute when the mean arterial pressure in the main artery supplying the organ is 100 mm Hg, which of the following flow conditions is inconsistent with the properties of autoregulation of blood flow when the mean arterial pressure in the supplying artery is reduced to 80 mm Hg? (For this question, do not consider any effects of activation of blood pressure reflexes in the response.) A. Blood flow = 75 mL/minute B. Blood flow = 85 mL/minute C. Blood flow = 90 mL/minute D. Blood flow = 99 mL/minute
A. Blood flow = 75 mL/minute
If mean capillary hydrostatic pressure = 30 mm Hg, interstitial hydrostatic pressure = 0 mm Hg, plasma oncotic pressure = 25 mm Hg, and interstitial oncotic pressure = 2 mm Hg, which of the following will create a situation in the capillary where there is no net reabsorption or filtration of fluid across the capillary?
A. Reducing plasma oncotic pressure to 22 mm Hg
B. Decreasing interstitial oncotic pressure to –4 mm Hg
C. Increasing interstitial hydrostatic pressure to 7 mm Hg
D. Increasing plasma oncotic pressure to 30 mm Hg
C. Increasing interstitial hydrostatic pressure to 7 mm Hg
What will occur in a person with intact cardiovascular neural reflexes when a sudden drop in mean arterial pressure from a normal value of 95 mm Hg to 70 mm Hg?
A. Constriction of cutaneous arterioles
B. Maximized carotid baroreceptor nerve firing rate
C. Contraction of cerebral arteries
D. Stimulation of the vasodepressor center in the medulla
A. Constriction of cutaneous arterioles
Heart rate is \_\_\_\_\_\_\_\_\_ in response to \_\_\_\_\_\_\_ firing rate of arterial baroreceptor nerves. A. increased; increased B. decreased; decreased C. increased; decreased D. decreased; zero
C. increased; decreased
If an individual’s resting heart rate is 75 beats/minute (bpm), complete blockade of the parasympathetic and sympathetic nerve activity to the heart will result in which of the following heart rates?
A. >75 bpm because of elimination of sympathetic activity to the heart
B. < 75 bpm because the parasympathetic nerves dominate heart rate at rest
C. >75 bpm because sympathetic nerves dominate heart rate at rest
D. >75 bpm because acetylcholine hyperpolarizes the SA node
D. >75 bpm because acetylcholine hyperpolarizes the SA node
What are receptors specific for?
Specific for stimulus
What is a slow adapting receptor also known as?
Tonic
what is a fast adapting receptor also known as?
Phasic
What are the 4 cutaneous sensory modalities?
Pain, Touch, Vibration, Temp
Final destination of the somatosensory system?
Post central Gyrus in the parietal lobe
Talk about Ruffinis’s endings
Contribute to the sensation of touch Have large receptor fields Slow adapting Skin stretch Slightly deeper than meissners and merkles but more superficial than pacianian
Talk about Pacinian corpuscles
Very rapidly adapting
Rapidly changing stimuli
VIbration
Deepest
Talk about Merkle’s Discs
Small receptor fields These allow for fine discrimination Slow adapting Detect steady pressure Most superficial
Talk about Meissner’s corpuscles
Small receptor fields These allow for fine discrimination Fast adapting Detect rapid changes Most superficial
What is the area of the skin supplied with afferent nerve fibers called?
Dermatomes
Talk about hair follicles
These have a nerve plexus that senses hair displacement.
Describe somatosensory system
- Final destination is Post central gyrus in parietal lobe
- It is the sensory network that monitors the surface of the body and conveys sensations from the skin and muscles.
- Has 4 cutaneous modalities (pain, touch, vibration, temp)
- Includes proprioception, this relates sensory info to the musculoskeletal system.
Name 3 types of receptor adaptation
(constant stimulus applied to all 3)
no adaptation = generator potential and action potential are constant and unchanged
fast adaptation
slow adaptation
Describe no receptor adaptation
no adaptation
There is constant action potential
(with constant stimulus applied)
no adaptation = generator potential and action potential are constant and unchanged
Describe slow receptor adaptation
Slow receptor adaptation
There is a slow gradual decline in action potential
(example is application of pressure)
(with constant stimulus applied)
slow receptor adaptation respond to constant stimuli with a gradual decline in the generator potential and the action potential frequency
Describe Fast receptor adaptation
Fast adapting receptor
There is a rapid decline in the action potential
(example is tension on a working muscle)
(with constant stimulus applied)
Fast adapting receptors have a generating and action potential that declines rapidly in response to a constant stimulus
Tonic adapting
The frequency of the action potential slowly decreases, but there is a relatively constant input of information. This means that there is a steady stimulus but that you are aware of the stimulus constantly.
Phasic Adapting
The frequency of the action potential rapidly drops off, you adapt to the stimulus. this can happen with some of the touch receptors or smell receptors. (you initially smell something but soon the smell doesn’t leave, you just stop noticing it.)
What is receptor adaptation
The decline in action potential generating when a constant stimulus is applied.
It is necessary so that constant environmental stimuli can be ignored preventing a flood of input info to the CNS.
The generator potential declines over time with constant stimulus.
Corpuscle
A nerve ending packaged in a bulb
The term hematocrit refers to:
A. The percentage of total blood volume that is plasma. This is normally about 45%
B. The percentage of total blood volume that is WBC. This is normally about 45%
C. The percentage of total blood volume that is RBC. This is normally about 55%
D. The percentage of total blood volume that is RBC. This is normally about 45%
D. The percentage of total blood volume that is RBC. This is normally about 45%
Which of the following cells are agranulocytes? A. Eosinophils B. Lymphocytes C. Neutrophils D. Polymorphonuclear leukocytes
B. Lymphocytes
A person with type A blood can safely donate RBCs to someone of type \_\_\_\_\_\_\_\_\_\_ and can receive RBCs from someone of type \_\_\_\_\_\_\_\_\_\_. A. O; AB B. AB; O C. A; B D. B; A
B. AB; O
Polycythemia vera is a hereditary neoplastic bone marrow disorder characterized by abnormally high red blood cell production. The steady state concentration of a substance in serum can provide additional information to confirm the diagnosis of the patient with polycythemia vera. Its level is typically low. This is in contrast to patients with secondary polycythemia, which is caused by respiratory conditions like emphysema that stimulate erythrocyte production. Which of the following substances is most likely tested? A. Albumin B. Bilirubin C. Erythropoietin D. Plasmin
C. Erythropoietin
John has AB negative blood. Which blood types can receive John’s blood? A. A negative B. B negative C. AB positive D. O negative
C. AB positive
An individual is diagnosed with myopia. Which lens will correct this visual defect? A. Flat B. Cylindrical C. Concave D. Convex
C. Concave
Where is the second-order neuron of somatosensory input located? A. Pons B. Medulla oblongata C. White mater of spinal cord D. Thalamus
B. Medulla oblongata
“old man eyes” is due to? A. distortion of the cornea B. loss of receptor cells in the foveal region of the retina C. shortening of the eyeball D. changes in the elasticity of the lens
D. changes in the elasticity of the lens
Which of the following vessels has the greatest compliance? A. Arteries B. Arterioles C. Capillaries D. Veins
D. Veins
All arteries and veins are innervated by postganglionic branches of the sympathetic nervous system. These nerves release norepinephrine onto the smooth muscle of veins and arteries causing these vessels to contract. The vascular effects of a generalized activation of the sympathetic nervous system would therefore be predicted to
A. Decrease venous compliance and decrease arterial flow resistance.
B. Increase venous compliance and increase arterial flow resistance.
C. Increase venous compliance and decrease arterial flow resistance.
D. Decrease venous compliance and increase arterial flow resistance.
D. Decrease venous compliance and increase arterial flow resistance.
Which of the following will exacerbate the pooling of blood that occurs in veins in the lower extremities of a patient when he or she assumes an upright position?
A. Activation of α-adrenergic receptors on veins by the sympathetic nervous system
B. Administration of the antianginal drug, nitroglycerin, which directly dilates veins more than arteries*
C. Administration of the emergency antihypertensive agent sodium nitroprusside, which directly dilates arteries more than veins
D. Placing the patient in supine position with his or her legs up
B. Administration of the antianginal drug, nitroglycerin, which directly dilates veins more than arteries
Which of the following is the result of an inward Na+ current?
A. Upstroke of the action potential in the sinoatrial (SA) node
B. Upstroke of the action potential in Purkinje fibers
C. Plateau of the action potential in ventricular muscle
D. Repolarization of the action potential in ventricular muscle
B. Upstroke of the action potential in Purkinje fibers
Which phase of the ventricular action potential coincides with diastole? A. Phase 1 B. Phase 2 C. Phase 3 D. Phase 4
D. Phase 4
During which phase of the ventricular action potential is the influx of Ca2+ highest? A. Phase 0 B. Phase 1 C. Phase 2 D. Phase 3
C. Phase 2
During which phase of the cardiac cycle does the mitral valve open?
A. Isovolumetric ventricular contraction
B. Rapid ventricular ejection
C. Isovolumetric ventricular relaxation
D. Rapid ventricular filling
D. Rapid ventricular filling
Cardiac output of the right side of the heart is what percentage of the cardiac output of the left side of the heart? A. 25% B. 50% C. 75% D. 100%
D. 100%
An increase in contractility will directly result in a decrease in which of the following? A. cardiac output B. end-systolic volume C. end-diastolic volume D. stroke volume
B. end-systolic volume
How many “order” neuron is somatosensory pathway?
It is a third order neuron pathway (3 neurons) but is sometimes considered a fourth order neuron if you count the relay from the post central gyrus to the association area where the information is interpreted.
The first order neuron of the somatosensory pathway?
Receptor neuron Goes from receptor to dorsal column Is an afferent (in) neuron It is located in the peripheral spinal nerve Axons ascends the white matter
The second order neuron of the somatosensory pathway?
Located in the dorsal column nuclei of the caudal medulla
The axon decussates (crosses over)
It ascends through the brainstem to the thalamus
It travels the medial lemniscus tract
The third order neuron of the somatosensory pathway?
Located in the thalamus
ascends to the primary somatosensory cortex
Travels via the white matter of the internal capsule
What is the site of decussation in somatosensory system?
Second order neuron
At level of medulla
Damage below decussation results in ipsilateral loss
Damage above decussation results in contralateral loss
What is the major somatosensory tract?
DCML
dorsal medial lemniscus tract
What is the main pathway for temperature or pain?
3 order neurons
glutamate or substance P is released by the first order neuron in afferent pain pathway
What is pain gating?
When non painful sensory stimulation is simultaneously applied (gentle rubbing)
Touch fibers enter the same dorsal root as the pain fiber send a collateral signal that synapses on inhibitory interneurons within the grey matter
This causes a release of opioids and inhibits transmission of pain in first and second order neurons
It basically confuses the brain with multiple signal and multiple inputs.
What is convergence projection?
This theory explains referred pain
Nerves share the same entrance point in the spinal cord
The CNS misinterprets the source of the pain
What two descending pathways can stimulate enkephalinergic interneurons (opiods)
A serotonergic pathway from the raphe nucleus of medulla and the norepinephrinergic pathway from the locus ceruleus of Pons
What is 2 point discrimination test?
Distance and differentiation between two points
Best at lips and fingertips
Worst at calf and lower back
less cortical tissue devoted in lower regions an a lower density of receptors
High discrimination is due to many merkels and meissners corpuscles
Large number of neurons in pathway
more cortical tissue devoted
What is left side of brain for?
Logic speech Verbal memory hearing sounds rational thought
What is right side of brain for?
Artistic Shape memory Hearing non verbal sounds Musical Facial recognition
What is accommodation
The ability to change the optical power of the lens to maintain focus at various distances.
Goal is to get light rays to converge on fovea centralis
macula lutea = dartboard
fovea centralis = bullseye
What is presbyopia
Reduced accommodation due to decreased elasticity in lens
Occurs with age
What is convergence reflex?
Occurs when focusing on a near object
Has 3 components (3 C’s)
Convergence of eyes to maintain a single image
Constriction of pupils of circular muscle
Contraction of ciliary muscles
Reflex is mediated by parasympathetic nerve of the eyes
Cornea does majority of focusing, lens does very little
Myopia
Nearsightedness
Light is focused in front of retina
Need concave (skinny) lens to correct
Eyeball is too long
Hyperopia
Farsightedness
Light is focused behind retina
Need convex (fat) lens to correct
Eyeball is too short
Astigmatism
Incorrect curvature of the eye in one plane
two different focal distances are produced depending on which
Need cylindrical lenses to fix
What are rods for?
Black and white (grey)
Allows high sensitivity to light
Allows objects to be seen in low intensity light
What are cones for?
High intensity light
Color vision
Located mostly in fovea
High visual acuity due to one cone cell synapsing with single bipolar cell
The single bipolar cell then synapses with single ganglion cell
Blue, green red
Why is visual acuity lower at the periphery?
More rods are at the periphery
many rods converge on a single ganglion cell
Fovea centralis
High visual acuity due to one cone cell synapsing with single bipolar cell
Bipolar cell then synapses with ganglion cell
no rods here, only cones
color vision
Where is vision at highest resolution
Central vision is highest resolution
poor in dim light
Peripheral vision is low resolution but good in dim light
Details about color blindness
It is a common condition
x linked recessive (more often in men)
Could be from a range of defects
Most commonly from a missing cone type
Light through the cells in order
Light passes through all the cells until it hits the photoreceptors where it is collected
The signal then moves from the photo receptors (rods & cones) to the horizontal cell
Then to the bipolar cell
the amacrine cell
the ganglion cell
the optic nerve (CNII)
the Optic chiasm
what is the blind spot
The optic disc
we should see the blind spot but our brain fills in the gap for us
What is phototransduction
The cascade of chemical and electrical events through which light energy is converted into receptor potential
What happens to rods and cones in the dark?
Rhodopsin does not absorb light
This allows for the secretion of the neurotransmitter glutamate
Glutamate is an inhibitory neurotransmitter
Glutamate inhibits the bipolar cell
the bipolar then does not secrete any of its neurotransmitter
this prevents the nerve fiber from being stimulated
What happens to rods and cones in the light
Rhodopsin absorbs light
this causes inhibition of glutamate secretion
this allows the bipolar cell to stimulate the optic nerve
Adaptation to the Light
walking out into the sunlight
Pupils constrict
Color vision and acuity below normal for 5-10 minutes
time is needed for pigment bleaching to adjust retinal sensitivity to light
Rods quickly bleach, become nonfunctional and cones take over
Adaptation to the Dark
Turning off the lights
Dilation of the pupils
in the dark rhodopsin of rods is regenerated
takes 1-2 minutes for night vision to function
after 20-30 minutes, the amount of rhodopsin is sufficient for eyes to reach maximum sensitivity
Why is vitamin a important for eyes
Maintains healthy epithelia and vision Vitamin A deficiency results in night blindness (rod cell dysfunction) Xerophthalmia (dry eyes prone to ulceration) Follicular hyperkeratosis (rough skin around hair follicles)
The visual pathway
Axons from the retinal ganglion enter the optic nerve of each eye
The optic nerve then meets the optic chiasm where they cross the midline
The optic tract leads tot eh lateral geniculate body of he thalamus where it synapses
Second order neurons go from the synapse of the geniculate body and follows a course to the primary visual cortex via optic radiation
Why do visual fields overlap
They overlap extensively to provide binocular vision
How are images precessed
light from the right half of the visual field projects onto the nasal half (inner) of the right retina, it will then cross over and go to visual cortex, the light also projects onto the temporal half (outer) of the left retina, where it stays on the same side and goes to the visual cortex in the occipital lobe
Auditory transduction
Sound waves are converted to electrical impulses which are then interpreted by the brain
Where are the structures of the middle and inner ear?
Encased in the temporal bone
Major difference between the perilymph and endo lymph
perilymph is much higher in potassium
What happens when the hair cells in the Organ of Corti are displaced
This causes potassium channels to open
The potassium then enters into the hair cells causing action potentials in the neurons
These neurons then converge as the cochlear nerve
Which part of the cochlea responds to low frequencies
The upper part
Which part of the cochlea responds to high frequencies
The lower part
Trace the path of a sound wave
External canal
Tympanic membrane
Malleolus
Incas
Stapes
Oval window
Perilymph in labyrinth
cochlea
Scala vestibuli (ascending)
Scala tympani (descending)
cochlear duct
endolymph (inside cochlear duct)
Vibration of the endolymph disturbs Reisner’s and basilar membranes
The organ of corti sits on the basilar membrane
When it vibrates it stimulates the organ of corti
The nerve impulses are stimulated by special hair cells that cover are covered by the tectorial membrane
As the basilar membrane vibrate, tiny hairs are bent against the tectorial membrane which triggers the hair cells to fire and send an impulse
This sends a signal to the brain via the cochlear nerve
Is deafness sensorineural or cinductive?
It can be both
conductive hearing loss can be caused by a defect in any structure i.e. Auricle, tympanic, ossicle etc.
sensorineural can be caused by a lesion of the ear
or could be a problem in relaying the signal to the brain
What is mechanotransduction
Displacement of the stereocilia towards the kinocilium opens non selective cation channels
potassium enters causing depolarization of the hair cell
depolarization then results in calcium entry and exocytosis of neurotransmitter
Neurotransmitter causes depolarization of auditory neuron
Is the vestibular system part of the cochlear system
No, they are separate systems but share a cranial nerve
A loud sound does not make you dizzy
different stimuli
How many structures does the vestibule have
2 structures
the utricle
the saccule
What do otolith organs do?
Detect tilting of head and linear acceleration
how do the otolith organs work?
Hair cells located in the sensory epithelium called macula
Tips of the hair cells call stereocilia project into a gelatinous cap which is covered in small calcium carbonate crystals called otoliths
Movement of the head displaces otoliths and bends the stereocilia
This results in a receptor potential
How do otoliths transduce information from a tilting head
Tilting head
This changes the angle and the direction of force that the otoliths create
Different degrees of tension depend on the orientation
All possible orientations are represented due to the utricle being vertical and the saccule being horizontal
Linear acceleration
How do otoliths transduce information from linear acceleration
This displaces the otoliths and excites the hair cells
when traveling at constant speed, no acceleration or deceleration is detected and results in feeling like standing still
Semicircular canals do what?
Semicircular canals detect rotational forces
3 semicircular canals at right angles to each other
This allows for all possible orientations
The hairs of each canal are in the swollen area called the ampulla
The cilia of the hairs project into the cupula, a gelatinous mass
Movements in the cupula generate a receptor potential in the hair cells
What senses angular forces
Semicircular canals
Superior canal = front to back (nodding)
Horizontal canal = left to right (shaking)
Posterior canal= left should to right shoulder
Canals are mirrored on each side of head
Stimulation on one side, causes inhibition on the other
What happens with constant rotation?
If rotation is constant for 30 secs, endolymph catches up and angular movement is now zero again
If constant rotation is suddenly stopped, this causes the endolymph to bend the cupula in the other direction.
What is rotational nystagmus
When you are spinning the eyes will move in the same direction as the spin until they cannot move anymore, then they will click back to the beginning and do it again.
Why is blood a connective tissue
Cells are separated by a matrix, in this case, plasma (ECF)
Functions of blood (4)
Transport
Homeostasis
Hemostasis
Immunity
Make up of blood
Plasma = 55% Formed elements (RBC, White cells, platelets) Buffy coat <1% (white cells, platelets)
What is plasmapheresis
The therapeutic exchange of plasma
Name some anticoagulants
heparin EDTA warfarin citrate Prevents calcium from binding, critical in clotting
What are the main osmotically active solutes in plasma
Sodium
Chloride
Bicarbonate
What is oncotic pressure
Proteins in the blood form oncotic pressure
Colloidal osmotic pressure
Plasma that has a pulling effect on fluid due to proteins
Relatively stable
What are some plasma proteins made in the liver?
Albumin (Osmotic pressure)
Globulin (alpha, beta, gamma) (Antibodies)
Fibrinogen (coagulation)
What is the electro status of plasma
Plasma is electroneutral
Name plasma lipids
Cholesterol
Triglycerides
Phospholipids
Name plasma lipoporteins
Apoprotein
lipoprotein
VLDL, LDL, HDL, IDL
Tests for liver function
ALP (hepatitis)
ALT (Bile duct obstruction)
AST (general liver damage)
Bilirubin (waste product of liver from RBC breakdown)
What are BMP and CMP used for?
Metabolic health
abnormalities can predict problems with fluid like edema and hypertension
name granulocytes (polynuclear)
neutrophil (bacteria)
Basophil (histamines)
eosinophil (worms)
Name agranulocytes (mononuclear)
NK cells, cytotoxic T cells Mature B cells (antibodies) Helper cells (virus, cancer cells) Suppressor T cells Monocytic cells (mononuclear)(become macrophages)
Where do all blood cells originate from
hematopoietic stem cell
Red bone marrow
axial skeleton
humorous and femur
What two progenitor cells do hematopoietic stem cells turn into
Common myeloid progenitor cells
(RBC, platelet, myeloblast [-phils], monocytes)
Common lymphoid progenitor
B cells, T cells
Information on red blood cells
less in females
45% in hematocrit is the norm
anemia is less RBC
Polycythemia is more RBC (thicker blood)
How is hematocrit calculated
(RBC volume/whole blood volume)x 100 = hematocrit %
RBC numbers
Hematocrit = 45%
Hemoglobin = 15
RBC =5 x 10x12
5,15,45
What are blood smear good for?
parasites hematological problems like sickle cell
Who can type A blood give and receive from
A can receive from A or O,
A can give to A or AB
Who can type AB blood give and receive from
AB can receive from anybody
AB can only give to AB
Who can a Rh negative person give to?
Rh negative can receive from any matching blood type, positive or negative
Rh positive can only receive from RH positive donors
Who can type O blood give and receive from
Type O can receive from only O
Type O can give to anyone
What are universal blood types
AB is universal recipient
O is universal donor
What are the agglutinations
A, B, AB
What is hemolytic disease of a newborn
Mother is Rh negative
child is Rh positive
Mother creates antibodies that don’t harm first baby,
second can become anemic du to this
RHOgam is treatment to prevent antibody D
How many hemoglobin per RBC
several hundred due to the concave disc shape
Hemoglobin binding
O2 binds reversibly to iron in heme (oxyhemoglobin)
CO2 binds reversibly to globin (carbaminohemoglobin)
CO binds almost irreversibly
Hemoglobin strucutre
it is a 4 protein molecule 2 alpha chains and 2 beta chains each chain contains an iron bound heme each heme binds an O2 molecule Total of 4 O2's
Mutations in hemoglobin
Mutations can occur in 5 gene loci This can result in abnormal production of hemoglobin Sickle cell Thalassemia hemoglobinopathies
What are changes in Hemoglobin’s size?
Macrocytes
microcytes
anisocytoses (varying)
What are changes in Hemoglobin’s shape?
poikilocytosis (irregular)
Echinocytes (Burred)
schistocytes (Fragments)
What are changes in Hemoglobin’s color?
Hypochromatic
Spherocytes
Target
What are changes in Hemoglobin’s immature cells?
Normoblasts
megaloblasts
reticulocytes
What is anemia
Decreased hemoglobin or decreased hematocrit both cause anemia
Decreased RBC production from bone marrow damage, renal failure, b12 deficiency,
Increased red blood cell loss from hemorrhage or hemolysis
Low iron
How Are RBCs recycled
RBS last about 120 days
Broken down in liver and spleen
cell fragments are phagocytized
Red pulp of spleen is RDB graveyard
How is hemoglobin recycled
Separated into heme and globin
Heme to biliverdin, bilirubin, bile, feces
globin is hydrolyzed to free amino acids
Is iron toxic?
Free iron is toxin and binds to transferrin
Red blood cell formation
takes 3- days
Stem cell then erythropoietin
goes though a process
just before becoming a mature red blood cell it is a reticulocyte the ejects its nucleus
How do blood cells get through blood vessels
diapedesis is the process of blood cells squeezing through blood vessels
What kind of loop is RBC formation
Negative feedback Hypoxemia (low RBC's) Sensed by kidney and liver Secretion of EPO stimulation of bone marrow accelerated erythropoiesis Increased RBC's Increased O2 transport no more hypoxemia problem fixed
What are monocytes
Turn into macrophages
APC antigen presenting cells
Take a piece of pathogen and make antibodies from it
What are first defensive cells to be recruited at site of inflammation
Neutrophils
Info on platelets
They come from megakaryocytes Lifespan of 7-10 days Thrombopoietin stimulates the megakaryocytes to release platelets in the bone marrow they have no nucleus have granules
Where is thrombopoietin produced
Thrombopoietin is produced in the liver and kidneys
3 mechanisms to maintain homeostasis
Vascular spasm
platelet plug
blood clotting
How platelets work
They secrete vasoconstrictors to help reduce blood loss
They stick together to form a plug
they secret clotting factors
they initiate formation of clot dissolving enzyme
They chemically attract neutrophils and monocytes
Hemostasis Vascular spasm mechanism
Vascular spasm
to prevent immediate loss of blood
Constriction of vessels
can be induced by pain, injury, serotonin from platelets
How does ADP work in clotting
Positive feedback ADP is released from platelets in break of vessel ADP attracts more platelets More platelets come and release more ADP ETC
Hemostasis platelet plug formation
Platelet plug formation
when vessel is broken, normally smooth lining (prostacyclin = platelet repellant) is interrupted and platelets stick tot exposed collagen. They build up and stick together to form a plug
ADP attracts more platelets (positive feedback until the break is sealed
Thromboxane A2 is an eicosanoid lipid
Hemostasis clotting formation
Last and most effective means of stopping blood loss
Fibrinogen is converted to fibrin to form framework of clot
Extrinsic pathway = factors released by damaged tissue begin cascade
Intrinsic pathway = factors found in blood begin cascade (platelet degranulation)
Calcium very important in clotting
Activate one factor, it can start clotting cascade
Disease that is from missing clotting factors
hemophilia
3 phases of coagulation
Phase 1 = Prothrombin activator
Phase 2 = Prothrombin II and thrombin II
Phase 3 = Fibrinogen I, Fibrin, Crosslinked mesh
Order of formation in coagulation
Start with prothrombin activator
That makes prothrombin II into Thrombin III
Then Thrombin III takes fibrinogen and makes fibrin (insoluble)
You add calcium, Thrombin III and a couple of the factors to the fibrin and you get a crosslinked mesh.
Coagulation summary
Injury Vascular spasm Platelet plug Coagulation Repair Fibrinolysis (clot breakdown)
How the clot is dissolved
Clot retraction occurs within 30 minutes
fibrinolysis
plasminogen converted into plasmin (fibrin dissolving enzyme)
Plasminogen gets converted to plasmin by precursor kallikrein
Plasmin then breaks fibrin polymer down
Clot dissolution
What factors does blood flow depend on
Difference in pressure between arteries and veins
How much total resistance there is in vascular system
High pressure to low pressure
When blood leaves the left ventricle, this is the highest point of pressure
What has the most significant point of control to capillary beds
Arterioles are the most significant point of control to capillary beds
Smooth muscle, outnumber all other arteries
more muscular
Pressure vs volume in ventricles
The pressure is different in the ventricles but the volume is the same
What type of pressure does the rate of flow depend on
It depends on the pressure difference not the absolute pressure
The greater the pressure difference, the greater the flow
Issues that affect flow
The longer the tube, the slower the flow
The smaller the radius the less the flow
Radius is the dominant variable
Double radius increases flow by 16
Vein general info
Old sock poor elasticity high compliance 60% of blood is in venous system low pressure
Artery general info
New sock High elasticity low compliance large composition of smooth muscle high pressure Elasticity and stretching help maintain pressure
Forces that contract or relax smooth muscle
Physical chemical hormonals paracrine receptor mediated sympathetic nerves
Non - Receptor mediated vasoconstrictors
Calcium
potassium
O2
Receptor mediated vasoconstrictors
epi norepi ach serotonin atp angiotensin II vasopressin (ADH) endothelin
Direct vasodilators
Nitric oxide
Hyperpolarization hypoxia hypercapnia acidosis cAMP cGMP
Vasoconstrictor receptor mediated
epi
histamines
adenosine
series vs parallel flow
disease can cause loss of parallel flow
angiogenesis (creation of new parallel arteries from exercise
Flow in parallel decreases resistance and increases flow
Distribution of blood pressure
Blood pressure stays pretty stable in large arteries
Drastic drop in arterioles due to increased resistance
capillaries have very low pressure
pressure continues to decline in venous system
almost zero at return to right atria
2/3 of blood in venous system
80% of that 2/3 is in small veins
MAP
Mean arteriole pressure
Average arterial pressure over a complete cardiac cycle
MAP is not an average
(2dbp +sbp) / 3
MAP is weighted towards DBP due tot he heart being in diastole 2/3 of time
Cardiac output
volume of blood each ventricle pumps in one contraction
CO = HR x SV
What happens to MAP if CO or TPR increase
It will increase
it will also decrease if either of these decreases
Factors that affect blood viscosity
RBC count
Polycythemia & dehydration increase viscosity and slow flow
Anemia & hypoproteinemia (decrease viscosity and speed flow)
What can a loss of plasma but not RBC’s cause
increased hematocrit, burns, severe dehydration, kidney disease
Vessel compliance info
If a vessel is compliant is will expand with fluid
disease and aging can lessen compliance
Vessels are stiffest at low pressure
Veins are most compliant (old sock)
Relationship between compliance and pressure of vessels
It is inverse
increase compliance, decrease pressure
decrease compliance, increase pressure
What are two major cell types of unique action potential
Myocyte = fast pacemaker = slow SA,AV
calcium induced calcium release
Cardiac muscle cells contract without nervous stimulation
pacemaker cells spontaneously generate action potentials
These spread through the gap junctions
The action potential spreads tot he t tubule which opens voltage gated calcium channels or “l type” channels
This allows for extracellular calcium to enter cell, calcium induced calcium release is triggered and the SR releases large amounts of calcium
Calcium to troponin C etc.
SERCA pumps put calcium back into SR (ATPases)
Node firing rate
SA 80-100 Athletes can slow Parasympathetic slows to about 70 AV 60-80 (ectopic) Bachman's bundle is for atria dispersal Long refractory period means no tetany, allows for diastole or relaxation
What cell or nodes have a plateau period
SA and AV node have no plateau
Conduction system and ventricular myocytes have plateau period
ECG P wave
Atrial depolarization (contraction) SA node fires
ECG PQ interval
AV node fires
ECG QRS
ventricular depolarization (contraction) Atrial Repolarization (relaxation)(hidden) AV valves close
ECG T wave
Ventricular repolarization (relaxation)
cardiac cycle
one complete cycle of the heart
systole is contraction
diastole is relaxation
mechanical and electrical events of heart
Electrical events precede mechanical events
Result of calcium entering
