Exam 5 - Brain and Cranial Nerves; Circulatory System: Blood; The Heart

Question 1

rostral

Answer 1

towards the forehead (brain)

higher (spinal cord, brainstem)

Question 2

caudal

Answer 2

towards the spinal cord (brain)

lower (spinal cord, brainstem)

Question 3

landmarks

Answer 3

cerebrum
cerebellum
brainstem

Question 4

cerebrum

Answer 4

cerebellar hemispheres
gyri (thick)
sulci (shallow)
longitudinal fissure

Question 5

longitudinal fissure

Answer 5

separates right and left hemispheres from each other

Question 6

brainstem

Answer 6

ends at foramen magnum of skull and CNS continues below as spinal cord

Question 7

corpus callosum

Answer 7

thick bundle of nerve fibers connecting the hemispheres at the bottom of the longitudinal fissure

Question 8

gray matter

Answer 8

superficial
neuron cell bodies
dendrites
synapses
cortex and nuclei

Question 9

white matter

Answer 9

deep
tracts: bundles of axons
myelinated

Question 10

meninges

Answer 10

dura mater
arachnoid mater
pia mater

Question 11

dura mater

Answer 11

periosteal layer (superficial)
meningeal layer (deep)

dural sinus

in certain places the dura folds inward to separate major parts of the brain:
falx cerebri
tentorium cerebelli
falx cerebelli

Question 12

dural sinus

Answer 12

spaces that collect blood that has circulated through the brain

separates periosteal and meningeal layer

superior sagittal sinus
transverse sinus

empties into jugular veins of neck

Question 13

falx cerebri

Answer 13

extends into longitudinal fissure separating right/left cerebral hemispheres

Question 14

tentorium cerebelli

Answer 14

separates cerebellum from overlying cerebrum (like a tent)

Question 15

falx cerebelli

Answer 15

separates right and left halves of cerebellum

Question 16

meningitis

Answer 16

inflammation of meninges caused by bacteria and viruses that invade CNS

most serious diseases of infancy and childhood

pia and arachnoid mater most often affected; from here, infection can spread to adjacent nervous tissue

can cause swelling of brain, cerebral hemorrhaging, death within hours

death can occur so suddenly that people who think they might be infected need to seek help immediately

freshman college students show slightly elevated incidence of meningitis, especially those living in the dorms

Question 17

signs and symptoms of meningitis

Answer 17

high fever, stiff neck, drowsiness, intense headache, vomiting

Question 18

diagnosis of meningitis

Answer 18

examining CSF for bacteria and WBCs via spinal tap in subarachnoid space

Question 19

ventricles

Answer 19

circulate CSF

lateral ventricle
3rd ventricle
4th ventricle

Question 20

lateral ventricles

Answer 20

hold CSF which passes through interventricular foramen to 3rd ventricle

Question 21

3rd ventricle

Answer 21

CSF passes through cerebral aqueduct to 4th ventricle

Question 22

4th ventricle

Answer 22

central canal

choroid plexus:
blood capillary mass
ependymal cells

Question 23

CSF

Answer 23

clear, colorless liquid
ventricles and canals of CNS
filtrate of blood plasma
flow through and around CNS

median aperture and lateral apertures lead to subarachnoid spaces (empties from 4th ventricle) and absorbed by arachnoid villi

not stationary:
continually flowing
driven partly by own pressure and partly by rhythmic pulsations of brain produced by heart beats

Question 24

purposes of CSF

Answer 24

buoyancy: brain hangs from fibroblast
weighs 1500g; only 50g in CSF

protection: keep brain from striking cranium
shaken baby syndrome/concussions

chemical stability: rinses metabolic waste
homeostatic regulation

Question 25

blood supply

Answer 25

brain = 2% of body weight receives 15% of blood consumes 20% of oxygen and glucose

Question 26

blood-brain barrier (BBB)

Answer 26

seals blood capillaries in brain tissue tight jxns and endothelial cells selective substance passing to brain

Question 27

blood-CSF barrier

Answer 27

ependymal cells with tight jxns no brain-CSF barrier

Question 28

circumventricular organs (CVO)

Answer 28

monitor blood chemistry no BBB in these areas of the 3rd and 4th ventricles

Question 29

medulla oblongata

Answer 29

begins at foramen magnum and ends at pons contains all nerve fibers that travel between brain and spinal cord contains cardiac center that regulates force and rate of heartbeat vasomotor center that regulates BP 2 respiratory centers that regulate rate and depth of breathing

Question 30

pons

Answer 30

several nuclei involved in basic physiological fxns: sleep respiration bladder control peduncles: attach to cerebellum continuation of previous structures

Question 31

midbrain

Answer 31

connects hindbrain to forebrain ``` made of several structures: central gray matter superior colliculi inferior colliculi substantia nigra ```

Question 32

central gray matter of midbrain

Answer 32

controls awareness of pain

Question 33

superior colliculi

Answer 33

fxns to visually track moving objects by reflexively turning eyes and head

Question 34

inferior colliculi

Answer 34

receive/process auditory input from lower levels of brainstem and relay it to other parts of brain (particularly thalamus)

Question 35

susbstantia nigra

Answer 35

improves motor performance by suppressing unwanted muscle contractions degeneration leads to uncontrollable muscle tremors of Parkinson's disease

Question 36

reticular formation definition

Answer 36

loosely organized web of gray matter that runs vertically through all levels of brainstem

Question 37

functions of reticular formation

Answer 37

``` somatic motor control cardiovascular control pain moderation sleep and consciousness habituation ```

Question 38

cerebellum

Answer 38

``` cerebellar hemispheres vermis cerebellar peduncles folia (gyri) arbor vitae deep nuclei purkinje cells ```

Question 39

diencephalon

Answer 39

thalamus hypothalamus epithalamus

Question 40

thalamus

Answer 40

ovoid mass at superior end of brainstem composed of several nuclei "gateway to cerebral cortex" passage for sensory input motor control memory and emotion

Question 41

epithalamus

Answer 41

pineal gland (endocrine gland)

Question 42

hypothalamus

Answer 42

major control center of autonomic nervous system and endocrine system ``` functions: hormone secretion autonomic effects thermoregulation food and water intake sleep and circadian rhythms emotional responses memory ```

Question 43

lobes

Answer 43

``` frontal parietal occipital temporal insula ```

Question 44

frontal lobe

Answer 44

cognition higher mental processes speech motor control

Question 45

parietal lobe

Answer 45

receives and interprets signals of general senses and taste

Question 46

occipital lobe

Answer 46

visiaul perception

Question 47

temporal lobe

Answer 47

``` hearing smell learning memory some vision and emotion ```

Question 48

insula

Answer 48

taste hearing visceral sensation

Question 49

cerebral white matter

Answer 49

projection tracts commissural tracts association tracts

Question 50

projection tracts

Answer 50

information from one cerebrum to rest of body

Question 51

commissural tracts

Answer 51

between hemispheres commissures corpus callosum

Question 52

association tracts

Answer 52

regions of same hemisphere

Question 53

cerebral cortex

Answer 53

covering surface of hemispheres 40% mass of brain stellate cells pyramidal cells neocortex

Question 54

stellate cells

Answer 54

receive sensory input | processes local info

Question 55

pyramidal cells

Answer 55

output neurons of cerebrum

Question 56

neocortex

Answer 56

makes up 90% of cerebral cortex 6-layers: vary in thickness, composition, synaptic connections, size of neurons, destination of axons layer IV thickest in sensory regions layer V thickest in motor regions all axons that leave cortex and enter white matter arise from layers III, V, VI developed 60 million years ago when there was a sharp increase in diversity of mammals attained highest development in primates

Question 57

basal nuclei

Answer 57

masses of cerebral gray matter buried deep and lateral to thalamus, deep w/in white matter brain centers: caudate nucleus putamen globus pallidus motor control

Question 58

limbic system

Answer 58

important center of emotion and learning gratification and aversion centers prominent components: cingulate gyrus hippocampus amygdala

Question 59

integrative brain fxns

Answer 59

primary cortex | association cortex

Question 60

primary cortex

Answer 60

regions that receive input directly from sense organs or brainstem, or issue motor fibers directly to brainstem

Question 61

association cortex

Answer 61

all regions other than primary cortex involved in interpretation of sensory input, planning, motor output, thought, memory

Question 62

sense organs

Answer 62

signals from sensory organs routed to areas of primary sensory cortex in cerberum from there, signals relayed to nearby association area where sensory experences integrated with memory

Question 63

special senses

Answer 63

``` vision hearing equilibrium taste smell ```

Question 64

vision

Answer 64

occipital lobe | primary visual cortex

Question 65

hearing

Answer 65

temporal lobe and insula | primary auditory cortex

Question 66

equilibrium

Answer 66

cerebellum | several brainstem nuclei

Question 67

taste

Answer 67

parietal lobe | primary gustatory cortex

Question 68

smell

Answer 68

temporal and frontal lobes | orbitofrontal cortex

Question 69

general senses

Answer 69

widely distributed through body with simple receptors touch, pressure, stretch, temperature, pain thalamus routes somatosensory signals to postcentral gyrus gyrus forms anterior border of parietal lobe: rises from lateral sulcus to crown of head descends into longitudinal fissure cortex of gyrus = primary somatosensory cortex diagrammed a sensory homunculus

Question 70

motor control

Answer 70

intention to contract skeletal muscle begins in motor association (premotor) area: plan behavior plan transmitted to neurons of precentral gyrus (primary motor area) which is most posterior gyrus of frontal lobe neurons here send signals to brainstem/spinal cord that result in muscle contraction diagrammed as motor homunculus

Question 71

other areas important for muscle control

Answer 71

basal nuclei and cerebellum nearly all areas of cerebral cortex send signals to basal nuclei

Question 72

language

Answer 72

Wernicke area: recognition of written/spoken language -formulates phrases Broca area: speech lesions in language area produce variety of language deficits called aphasias

Question 73

emotion

Answer 73

different areas: hypothalamus and amygdala many important aspects of personality depend on intact and fxnal amygdala and hypothalamus

Question 74

cognition

Answer 74

acquire and use knowledge association areas of cortex parietal lobe prefrontal cortex cerebellum

Question 75

basal nuclei in muscle control

Answer 75

basal nuclei process signals from cerebral cortex, issue output to thalamus which sends signal back to cerebral cortex - also controls highly practiced behaviors that require little though (writing, tying shoes) - control onset/cessation of planned/repetitive movements at shoulder/hip during walking - lesions cause movement disorders called dyskinesias

Question 76

cerebellum in muscle control

Answer 76

cerebellum aids in: learning motor skills, maintains muscle tone and posture, smooths muscle contractions, coordinates eye and body movements, coordinates motions of different joints

Question 77

amygdala in emotion

Answer 77

important center of human emotion - receives processed info of vision, hearing, taste, smell and general somatosensory and visceral senses - allows us to mediate emotional response to stimuli such as foul taste or pleasant music - especially important for fear

Question 78

output of emotion

Answer 78

output goes in 2 directions: - hypothalamus and lower brainstem: somatic and visceral motor systems (heart race, hair stand up) - prefrontal cortex: mediates conscious control and expression of emotions

Question 79

parietal lobe in cognition

Answer 79

attention to objects in environment - lesions produce contralateral neglect syndrome in which patient seems unaware of objects on one side of body - fail to recognize, dress, and take care of one side of body or ignore all words on 1 side of page

Question 80

prefrontal cortex in cognition

Answer 80

distinct human abilities - abstract thought, foresight, judgment, responsibility, sense of purpose, sense of socially appropriate behavior - lesions render a person easily distracted from a taste, irresponsible, exceedingly stubborn, unable to anticipate future events, incapable of any ambition or planning for future

Question 81

cerebellum in cognition

Answer 81

many cognitive fxns - short term predictions about movement - lesions cause emotional overreaction and problems with impulse control - many children with ADHD have abnormally small cerebellums

Question 82

procedural memory

Answer 82

retention of motor skills

Question 83

declarative memory

Answer 83

retention of events and facts that one can put into words (names, dates, facts)

Question 84

amygdala in memory

Answer 84

creates emotional memories

Question 85

hippocampus in memory

Answer 85

creates long term declarative memories - learns from sensory input during experience - later, probably when sleeping, plays memory repeatedly to cerebral cortex which forms longer lasting memories (memory consolidation) - lesions can abolish ability to form new declarative memories

Question 86

cerebral cortex in memory

Answer 86

stores long term memories

Question 87

Wernicke area in memory

Answer 87

memory of language

Question 88

superior temporal lobe in memory

Answer 88

memory of faces

Question 89

prefrontal cortex in memory

Answer 89

stores memories of one's social role, appropriate behavior, goals, plans

Question 90

procedural memories stored in:

Answer 90

motor association area, basal nuclei, cerebellum

Question 91

cerebral lateralization

Answer 91

unique hemispherical fxns

Question 92

left hemisphere lateralization

Answer 92

categorical hemisphere spoken and written analytical reasoning employed in fields such as science, math breaks information into fragments and analyzes it

Question 93

right hemisphere lateralization

Answer 93

representational hemisphere perceives information in more integrated, holistic way imagination and insight musical and artistic skill perception of patterns and spatial relationships comparison of sights, sounds, smells, tastes

Question 94

cranial nerves

Answer 94

``` I olfactory II optic III oculomotor IV trochlear V trigeminal VI abducens VII facial VIII vestibulocochlear IX glossopharyngeal X vagus XI accessory XII hypoglossal ```

Question 95

trigeminal neuralgia

Answer 95

syndrome characterized by recurrent episodes of intense stabbing pain in trigeminal nerve usually occurs in women over 50 pain lasts a few seconds to a couple minutes but can happen 100+ times a day pain usually in specific zone of face can be triggered by touch, drinking, tooth brushing, washing face

Question 96

trigeminal neuralgia treatment

Answer 96

pain relievers give limited relief severe cases treated by cutting nerve, which deadens most other sensations in that side of face

Question 97

Bell's Palsy

Answer 97

degenerative disorder of facial nerve, probably due to virus paralysis of facial muscles on one side of face resulting in distortion of facial features may interfere with speech prevent closure of eye, sometimes inhibit tear secretion may appear abruptly and often disappears spontaneously w/in 3-5 weeks

Question 98

Alzheimer's disease

Answer 98

recent event memory loss reduced attention span disorientation atrophy of gyri of cerebral cortex and hippocampus

Question 99

Parkinson's disease

Answer 99

paralysis agitans or parkinsonism loss of motor fxn degeneration of substantia nigra (dopamine-releasing cell)

Question 100

circulatory system

Answer 100

heart, blood vessels, blood adults have 4-6 L of blood

Question 101

hematology

Answer 101

study of blood

Question 102

fxns of circulatory system

Answer 102

transport protection regulation

Question 103

blood components

Answer 103

blood matrix blood plasma

Question 104

blood

Answer 104

liquid connective tissue composed of cells and extracellular matrix

Question 105

matrix

Answer 105

blood plasma light yellow fluid that makes up over half blood vol. contains formed elements: cells and cell fragments (RBCs, WBCs, platelets)

Question 106

blood plasma

Answer 106

``` 52% of blood 92% water nutrients electrolytes nitrogenous wastes hormones gases proteins -albumin -globulins -fibrinogen -others ```

Question 107

erythrocytes

Answer 107

``` RBCs discoid anucleated lack many organelles 4.6-6.2 million/uL in men 4.2-6.2 million/uL in women most abundant formed element in blood ```

Question 108

fxns of erythrocytes

Answer 108

pick up oxygen from lungs and deliver to tissues pick up CO2 from tissues and unload onto lungs

Question 109

hemoglobin

Answer 109

iron-containing gas-transport protein found in RBC four globins with heme group ferrous iron in center bind oxygen

Question 110

erythrocyte life cycle

Answer 110

originate from pluripotent stem cells last ~120 days as RBC ages, membrane proteins deteriorate and membrane grows fragile: ruptures eventually while flexing through narrow capillaries spleen = erythrocyte graveyard - RBCs have hard time passing thru small channels - old cells become trapped, broken up, destroyed

Question 111

erythropoiesis

Answer 111

RBC production

Question 112

hemopoiesis

Answer 112

formed element production

Question 113

blood types

Answer 113

several genetically determined blood groups ABO and Rh most common blood cell contains antigens plasma contains antibodies RBC antigen and plasma antibody determine compatibility of donor and recipient blood in transfusions person w/ type A has ant9-B antibodies in plasma and A antigens on cell - B blood: anti-B antibodies would attack donor blood - RBC's would agglutinate (clump) obstructing circulation w/ deadly consequences

Question 114

bone marrow transplant

Answer 114

can treat leukemia, sickle cell anemia replace cancerous/defective marrow w/ donor stem cells in hopes they will rebuild normal marrow and blood cells chemo or radiation first destroys defective marrow and eliminates immune cells (T cells) that would normally attack donated marrow marrow drawn from sternum or hip bone and injected into patients' circulatory system donor stem cells colonize marrow cavities, build healthy marrow

Question 115

drawbacks of bone marrow transplant

Answer 115

finding compatible donors surviving T cells may attack marrow, donor T cells may attack patients tissues immunosuppressant drugs for life (vulnerable to infection) infections from donated marrow 1/3 patients die from treatment complications

Question 116

cord blood transplants

Answer 116

placental blood = alternative - contains more stem cells than adult bone marrow - less likely to carry infectious microbes can be harvested from umbilical cord, stored, frozen at cord bank immature immune cells less tendency to attack recipient's tissue - lower rejection rate - not as close a match required btwn donor and recipient have successfully treated leukemia and other blood diseases

Question 117

leukocytes

Answer 117

``` WBCs least abundant formed element types -granulocytes -neutrophils -eosinophils -basophils -agranulocytes -monocytes -lymphocytes ```

Question 118

neutrophils

Answer 118

most abundant WBCs (60-70%) nucleus clearly visible w/ 3-5 lobes young neutrophils have undivided nucleus shaped like band (band cells) also called polymorphonuclear leukocytes (polys) because of varied nuclear shapes main task: destroy bacteria

Question 119

neutrophila

Answer 119

rise in neutrophil count in response to bacterial infection

Question 120

eosinophils

Answer 120

2-4% of WBCs secrete chemicals that weaken/destroy large parasites like hookworms or tapeworms phagocytize and dispose of inflammatory chemicals and allergens

Question 121

eosinophilia

Answer 121

eosinophil increase in response to allergies, parasitic infections, collagen diseases, diseases of spleen and CNS

Question 122

basophils

Answer 122

rarest WBC (.5%) secrete histamine and heparin to aid body's defenses release chemical signals that attract eosinophils and neutrophils to a site of infection

Question 123

monocytes

Answer 123

largest WBC but only 3-8% monocyte count rises in inflammation and viral infections leave bloodstream (diapedesis) and transform into large tissue cells called macrophages highly phagocytic cells

Question 124

lymphocytes

Answer 124

smallest WBC 2nd most abundant - 25-33% defend against viruses and cancer most involved in specific immunity

Question 125

specific immunity

Answer 125

defense in which body recognizes an antigen it has encountered before and mounts such a quick response the person might not even know they were ill

Question 126

leukopoiesis

Answer 126

WBC production begins w/ pluripotent stem cells which eventually produces 3 cell lines: myeloblasts monoblasts lymphoblasts

Question 127

myeloblasts

Answer 127

differentiate into granulocytes: neutrophils, basophils, eosinophils

Question 128

monoblasts

Answer 128

turn into monocytes

Question 129

lymphoblasts

Answer 129

Turn into 3 types of lymphocytes: B cells T cells natural killer cells - kill pathogen directly

Question 130

complete blood count (CBC)

Answer 130

common clinical procedure gives information such as: - # RBCs, WBCs, platelets - % each WBC type (differential WBC count) - hematocrit - RBC size (mean corpuscular volume MCV) - hemoglobin concentration (mean corpuscular hemoglobin MCH)

Question 131

platelets

Answer 131

small fragments of megakaryocyte aide in blood clotting produced through thrombopoiesis live for about 10 days hemostasis: cessation of bleeding

Question 132

RBC disorders

Answer 132

dietary deficiency of iron or certain vitamins can cause nutritional anemia (iron, B12, folate) radiation, viruses, poisons can cause anemia by destroying bone marrow

Question 133

hemolytic anemia

Answer 133

rapid RBC destruction exceeds rate of erythropoiesis can result from variety of poisons, drug rxns, sickle-cell disease, malaria

Question 134

hemorrhagic anemia

Answer 134

RBC deficiency from bleeding

Question 135

thalassemia

Answer 135

hereditary blood disease among people of mediterranean descent deficient hemoglobin synthesis -RBC count reduced and existing RBCs are microcytic (small) and hypochromic (pale)

Question 136

polycythemia

Answer 136

excess RBC count from bone marrow cancer or abnormally high oxygen demand (excessive exercise) or low oxygen supply thick blood sludges in vessels, increasing BP, putting strain on heart

Question 137

leukopenia

Answer 137

WBC deficiency from heavy metal poisoning, radiation, exposure, infectious diseases leaves a person susceptible to opportunistic infections

Question 138

leukocytosis

Answer 138

abnormally high WBC count from infection or allergy also from emotional stress and dehydration

Question 139

leukemia

Answer 139

cancer of hemopoietic tissues that results in high WBC WBC's immature and incapable of performing normal defensive roles

Question 140

thrombocytopenia

Answer 140

decreased platelets from leukemia, radiation results in impaired clotting when vessel is injured also in increased bleeding b/c of loss of normal blood vessel maintenance fxn of platelets

Question 141

sickle cell disease

Answer 141

hereditary defect of hemoglobin occurring mostly among people of African descent - defective gene - RBCs become elongated, stiffened, pointed deformed, inflexible cells can't pass thru blood capillaries - tend to adhere to each other and to capillary wall - congregate and block circulation obstruction of circulation produces severe pain and can lead to kidney or heart failure, stroke, paralysis -spleen removes defective RBCs faster than they can be replaced, leading to anemia and poor physical and mental development w/o treatment, death by age 2 advances in treatment have raised life expectancy to over 50 originated in Africa where millions suffer from malaria - malarial parasites cannot survive in RBcs w/ hemoglobin defect - confers resistance to malaria

Question 142

circuits

Answer 142

pulmonary and systemic circuits right half of heart supplies pulmonary circuit left half of heart supplies systemic circuit

Question 143

pulmonary circuit

Answer 143

carries blood to lungs for gas exchange and returns to heart

Question 144

systemic circuit

Answer 144

supplies blood to every organ of body

Question 145

heart

Answer 145

in thoracic cavity btwn lungs and deep to sternum from superior to inferior points, tilted left

Question 146

pericardium

Answer 146

double-walled sac enclosing heart contains pericardial fluid secreted by serous layer of pericardial sac -fluid lubricates membranes and allows heart to beat with minimal friction

Question 147

pericarditis

Answer 147

inflammation of pericardium membranes become rough, produce painful friction rub with each heartbeat

Question 148

heart wall

Answer 148

3 layers: thin epicardium covering external surface thick muscular myocardium in middle thin endocardium lining interior of chambers consists primarily of cardiac muscle arranged in spirals called the myocardial vortex -causes heart to contract with a twisting or wringing motion that enhances ejection of blood also has CT framework of collagen and elastic fibers called fibrous skeleton

Question 149

epicardium

Answer 149

serious membrane on heart surface

Question 150

endocardium

Answer 150

lines interior of heart chambers

Question 151

myocardium

Answer 151

in the middle thickest and performs work of heart

Question 152

heart chambers

Answer 152

4 (R/L atria and ventricles) ``` also: auricles coronary sulcus anterior/posterior interventricular sulcus interatrial septum pectinate muscles interventricular septum trabeculae carneae ```

Question 153

atria

Answer 153

superior thin walled receiving chambers for blood returning to heart each has small earlike extension called an auricle that slightly increases volume separated by interatrial septum

Question 154

ventricles

Answer 154

pumps that eject blood into arteries and keep it flowing around body separated by more muscular interventricular septum R ventricle pumps blood only to lungs (moderately muscular) L ventricle pumps blood through entire body (2-4 times thicker)

Question 155

valves

Answer 155

AV valves - right/tricuspid - left/bicuspid/mitral tendinous chords papillary muscles semilunar valves - pulmonary - aortic valves opened and closed by BP changes

Question 156

arterial supply

Answer 156

R/L coronary artery off aorta L coronary artery gives off two branches: - anterior interventricular branch - cirumflex branch

Question 157

myocardial infarction (MI)

Answer 157

fatty deposit or blood clot in coronary artery protection from MI's come from arterial anastomoses

Question 158

coronary artery disease

Answer 158

narrowing of coronary arteries resulting in insufficient blood flow to maintain myocardium (atherosclerosis) MI's can occur when artery becomes so occluded that cardiac muscle begins to die from lack of oxygen partial obstruction of an artery can cause temporary sense of heaviness and chest pain called angina pectoris when artery constricts

Question 159

venous drainage

Answer 159

veins empty into coronary sinus

Question 160

conduction system

Answer 160

cardiac mycotyes are autorhythmic: electrically discharge at regular time intervals some mycotyes lose ability to contract and become specialized for generating and conducting electrical signals -make up cardiac conduction system which allows heart chambers to coordinate with each other

Question 161

SA node (R atrium pacemaker) leads to...

Answer 161

atrium

Question 162

atrium leads to...

Answer 162

``` AV node (lower end of interatrial septum) -electrical gateway to ventricles ```

Question 163

AV node leads to...

Answer 163

``` AV bundle (bundle of His) -L/R branches to interventricular septum and apex) ```

Question 164

AV bundle leads to...

Answer 164

Purkinje fibers | -from lower end of bundle branch and turn upward to spread through ventricular myocardium)

Question 165

prental heart

Answer 165

one of earliest organs to begin fxning in embryo - 1st traces appear in week B - by 22-23 days:already beating - by day 24, circulating blood 1st audible heartbeat: 20 weeks interatrial septum begins to form at end of week 4 and well-established by 33 days (except for foramen ovale btwn atria, which persists through birth) interventricular septum appears at end of week 45 and is complete by end of week 7

Question 166

heart changes at birth

Answer 166

no pumping in fetal heart b/c lungs not fxnal - most blood bypasses pulmonary circuit by way of two shunts: - foramen ovale - ductus arteriosus at birth lungs inflate -sudden pressure change causes flap of tissue to seal foramen ovale and blood can no longer bypass lungs in most people, tissues grow together and permanently seal foramen -fossa ovalis

Question 167

foramen ovale

Answer 167

opening through interatrial septum in fetal heart some blood entering R atrium passes through opening directly into L atrium, then to L ventricle and sytemic circuit

Question 168

ductus arteriosus

Answer 168

short vessel from base of L pulmonary artery to aorta in fetal heart most blood from R ventricle pumped into pulmonary trunk takes bypass directly into aorta instead of usual path to lungs

Question 169

aging heart

Answer 169

stiffening of arteries normally when ventricles eject blood, arteries expand to accommodate surge in pressure - arteries stiffened by age can't expand - resist blood flow more than younger arteries - heart has to work harder - heart grows (ventricles enlarge, especially L) ventricular hypertrophy

Question 170

ventricular hypertrophy

Answer 170

heart wall and interventricular septum can become so thick that space within ventricles is severely diminished CO declines to point of heart failure

Question 171

Leukocyte pneumonic

Answer 171

``` 60 - never - neutrophil 30 - let - lymphocyte 8 - my - monocyte 3 - engine - eosinophil 0 - blow - basophil ```

Question 172

Bradycardia

Answer 172

Heart beats too slow

Question 173

Tachycardia

Answer 173

Heart beats too fast