Midterm Flashcards
Astrocytes:
a) Are important in the repair of brain injuries and neural scar formation
b) Induce formation of the blood brain barrier
c) Physically support neurons
d) Take up excess K from the brain ecf
e) All the above
e) All the above
Which of the following is NOT accomplished by the cerebral cortex?
a) Conscious sensory perception
b) Control of breathing, circulation, and digestion
c) Language ability
d) Personality traits
e) Voluntary initiation of movement
b) control of breathing, circulation, and digestion
The left cerebral hemisphere normally excels in ALL of the following EXCEPT:
a) Language ability
b) Logical and analytical tasks
c) Math skills
d) Music ability
e) Verbal tasks
d) music ability
What part of the brain controls thirst and urine output, food intake, and body temp among other things?
a) Basal nuclei
b) Cerebral cortex
c) Hypothalamus
d) Pons
e) Thalamus
c) Hypothalamus
The overall functioning of the ANS contributes to:
a) The conservation of energy resources when stress levels are low
b) Homeostasis
c) Mobilization of energy reserves when stress levels are high
d) Suppression of nonvital activities when stress levels are high
e) All of the above
e) All of the above
The blood brain barrier
a) Consists of the astrocyte processes that encircle the brain capillaries
b) Is formed in part by the tight junctions between the brain capillary cells
c) Limits the direct exchange of materials between the CSF and brain
d) All the above
b) Is formed in part by the tight junctions between the brain capillary cells
Parasympathetics stimulation_______heart rate and _____the motility in the digestive tract.
a) Does not affect, increases
b) Decreases, increases
c) Decreases, decreases
d) Increases, decreases
e) Increases, increases
b) Decreases, increases
What part of the brain plays a vital role in short term memory involving the integration of various related stimuli and is crucial for consolidation of short term memory into long term memory?
a) Basal nuclei
b) Cerebellum
c) Cerebral cortex
d) Hippocampus
e) Hypothalamus
d) Hippocampus
What region of the brain houses the centers that control the sleep-wake cycle?
a) Hypothalamus
b) Cerebral cortex
c) Brain stem
d) Thalamus
e) none of the above
c) Brain stem
The primary cortex is located:
a) In the temporal lobe
b) Posterior to the central sulcus
c) In the occipital lobe
d) Anterior to the central sulcus
e) In the parietal lobe
d) Anterior to central sulcus in frontal lobe
What is an oligodendrocyte (CNS)
- most common glial cell
- Each form myelin sheath around axons
Purpose of afferent division of the PNS
-Bring sensory information from receptors
Purpose of efferent division of the PNS
-carries motor command to effectors
What is dura mater?
-the outermost layer covering the spinal cord and brain
What is arachnoid mater?
-the middle layer covering the spinal cord and brain
What is pia mater?
-a thin layer that adheres directly to the surface of the spinal cord and brain
What are denticulate ligaments?
-thickenings of the pia mater that suspend the spinal cord in the middle of it’s dural sheath
What is the function of CSF?
Mechanical protection -floats brain & softens impact Chemical protection -optimal ionic concentrations Circulation -nutrients & waste to/fro blood
What is the origin of CSF?
-choroid plexus which are capillaries covered by ependymal cells Found -2 lateral ventricles -3rd ventricule -4th ventricule
What are the arachnoid villi?
-grapelike clusters of arachnoid that penetrate dural venous sinus to reabsorb CSF
What are the 7 functions of the hypothalamus?
- major regulator of homeostasis
- controls the ANS
- produces hormones
- regulates emotional and behavioral patterns
- regulates satiety and thirst center
- aids with control of body temp
- regulates circadian rhythms
What are the functions of the thalamus?
- contains nuclei that serve as relay stations for all sensory impulses(except smell) to the cerebral cortex
- registers conscious recognition of pain and temperature
- essential role in awareness and cognition
What are the 7 major groups of thalamic nuclei on each side?
- anterior nucleus
- medial nuclei
- lateral nuclei
- ventral group
- intralaminar nuclei
- midline nucleus
- reticular nucleus
What are the functions of the thalamus?
- contains nuclei (RAS) that serve as relay stations for all sensory impulses(except smell) to the cerebral cortex
- registers conscious recognition of pain and temperature
- essential role in awareness and cognition
What is the function of limbic system?
emotion and memory
What is the Reticular Activating System?
- Nuclei connected from brain stem to cerebral cortex
- regulate sleep-wake transition
- regulate between relaxed wakefulness and high alertness
What is the name of cranial nerve I and its function?
Olfactory nerve- smell
What is the name of cranial nerve III and its function?
Oculomotor nerve- movement of eyeball
What is the name of cranial nerve V and its function?
Trigeminal nerve- Sensation of touch, taste, mastication, & movement of lower jaw
What is the name of cranial nerve VIII and its function?
Vestibulocochelar nerve- hearing
What is the name of cranial nerve XII and its function?
Hypogloassal nerve- tongue movement
Effects of the ANS on the lungs
Sympathetic -dilation of bronchioles -inhibition of mucus secretion Parasympathetic -constriction of bronchioles -stimulation of mucus secretion
Effects of the ANS on digestive tract
Sympathetic -decreased motility -contraction of sphincters -inhibition of digestive secretions Parasympathetic -increased motility -relaxation of sphincters -stimulation of digestive secretions
Effects of the ANS on genitals
Sympathetic
-ejaculation & orgasmic contractions
Parasympathetic
-erection (caused by dilation of blood vessels in penis and clitoris)
What is the purpose of the Sarcoplasmic Reticulum?
- Stores Ca in relaxed muscle
- release of Ca triggers muscle contraction
What protein is present in the thick myofilaments of skeletal muscle
Myosin
What proteins are present in the thin myofilaments of skeletal muscle?
Actin, Troponin, Tropomysosin
Characteristic of Troponin
Possesses binding sites for CA ions
Characteristic of Actin
Possesses binding site for myosin
Characteristic of Myosin
Possesses binding site for actin and ATP
3 Characteristic of smooth muscle
- Ca++ ions come mostly from extracellular fluid
- actin and myosin are both present
- most cells are capable of self-excitation
Characteristic of skeletal muscle
-actin, myosin, and troponin is present
In smooth muscles, what do Ca++ ions bind to?
Calmodulin
When does the depolarizing phase of the action potential of skeletal muscle cells end?
Na+ inactivation gates close
In smooth muscle, the binding of Ca++ ions activates what enzyme?
Myosin light chain kinase
What is the role of tropomyosin in relaxed muscle cells?
Blocks active sites of 6 or 7 actions and prevents myosin from binding to them
What are the 4 steps in the contraction cycle?
-ATP hydrolysis
-Attachment of myosin to actin
-“Power stroke”
Detachment of myosin from actin
What happens in contraction cycle step 1?
Myosin heads hydrolyze ATP and become reoriented and energized
What happens in contraction cycle step 2?
Myosin heads bind to actin, forming crossbridges
What happens in contraction cycle step 3?
Myosin crossbridges rotate toward center of the sarcomere
What happens in contraction cycle step 4?
As myosin heads bind ATP, the cross bridges detach from actin
What does ATP do to myosin?
Energizes the myosin causing the myosin head to teach and pull on the thin filament
What are the 4 steps of the sliding filament mechanism of action?
1-myosin crossbridges pull on thin filaments
2- thin filaments slide inward
3- Z discs come toward each other
4-Carcomeres shorten. Muscle fibers shorten. Muscle shortens
*thick and thin filaments do not change in length
What is a motor unit?
One motor neuron and the muscle fibers it innervates
Where are the semilunar valves? And what is their purpose?
Located between pulmonary artery and right ventricle and the aorta and the left ventricle. Allow blood to flow into artery but doesn’t allow blood to flow back into ventricle.
Which ventricular wall is thicker and why?
Left ventricular wall is thicker due to the higher forces needed to pump blood to the body
What is the purpose of the AV nodal delay?
Gives atria time to contract
What is the purpose of an ECG?
To detect and record the action potential of all active cells
What does the P wave represent?
atrial depolarization
What does the P-Q interval represent?
conduction time from atrial to ventricular excitation
What does the QRS complex represent?
Ventricular depolarization
What does the T wave represent?
ventricular repolarization
What does the T wave represent?
ventricular repolarization
calculation for stroke volume
SV= CO/HR
How do arteries serve as rapid transit passageways?
Due to large radius, arteries offer little resistance to blood flow
What is the pulse pressure?
difference between systolic and diastolic pressure. If BP is 120/80, pulse pressure is 40
What is the pulse pressure?
difference between systolic and diastolic pressure. If BP is 120/80, pulse pressure is 40
Formula for calculating mean arterial pressure
MAP= diastolic pressure + 1/3 pulse pressure
What is the function of the baroreceptors?
monitor stretching of the walls of blood vessels and the atria
What 3 things do the baroreceptor reflexes do in the carotid sinus?
- swellings in internal carotid artery wall
- relay info from glossopharyngeal nerve to cardiovascular center in medulla
- maintains normal BP in the brain
What 3 things do the baroreceptor reflexes do in the aortic reflex?
- receptors in wall of ascending aorta
- info elated via vagus nerve to cardiovascular center
- maintains general systemic BP
What is the capillary wall composed of?
Of only a single layer of endothelium and a basement membrane
What is circulatory shock?
BP falls so low that adequate blood flow to the tissues can no longer be maintained
What are the four types of circulatory shock?
- Hypovolemic (low volume)
- Cardiogenic (heart produced)
- Vasogenic (vessel produced)
- Neurogenic (nerve produced)
Name 2 parts of hemoglobin molecule
Globin-protein composed of 4 highly folded polypeptide chains
Heme-4 iron containing nonprotein groups, each bound to 1 of polypeptides
How many oxygen molecules can each hemoglobin carry from the lungs to tissue cells?
4 oxygen molecules
What and how much does hemoglobin transport from tissue cells to lungs for release?
transports 23% of total CO2 waste
What is Carbonic anhydrase?
enzyme found in red blood cells that assists with conversion of metabolically produced CO2 into HCO3-
do red blood cells contain DNA, nucleus, or organelles?
no
How long does a red blood cells live for?
120 days
How are worn out cells removed?
by fixed macrophages in spleen and liver
What is erythropoiesis?
Erythrocyte production that occurs in bone marrow at rate of 2-3 million cells/second
What are the 3 functions of eosinophils?
- release histamine to slow down inflammation caused by basophils
- attack parasitic worms
- phagocytize antibody-antigen complexes
What are the 3 functions of basophils?
- involved with inflammatory & allergy reactions
- leave capillaries & enter connective tissue as mast cells
- release heparin, histamine, & serotonin
What are the functions of monocytes?
- continue to grow and mature into macrophages
- become professional phagocytes
What is the function of neutrophils?
fastest response of WBC to bacteria
- release lysozymes which destroy/digest bacteria
- release defense proteins that act like ABx
- release strong oxidants that destroy bacteria
Where and how are platelets formed?
Formed in bone marrow. myeloid stem cells ->megakarocyte-colony forming cells ->megakaryoblast ->megakaryocytes whose cell fragments form platelets
How long are platelets life span?
average 10 days
Goal of the coagulation cascade
to form a more efficient clot through either intrinsic or extrinsic pathways
What is prostacyclin?
Compound released from normal endothelium with nitric oxide to prevent platelets from aggregating adjacent to vessel injury
What is hemophilia?
excessive bleeding caused by deficiency of one of the factors in the clotting cascade
Acute bacterial infections release which leucocyte?
Neutrophils
What chemical signal released by healthy endothelial tissue prevents the overgrowth of platelet plugs?
prostacyclin
