Test 3 Flashcards
During ventricular fibrillation, there is no coordinated ventricular contraction. What effect does this have on cardiac output?
no cardiac output
If the SA node stopped functioning what result would you see on the EKG?
P waves absent, hrt ~50 bpm
TRUE OR FALSE: The refractory period in a cardiac muscle fiber lasts almost as long as the entire muscle twitch
True
In cardiomyocytes action potentials, voltage gated Na+ channels are in ___ cells open during ___
contractile; depolarization
In the myocardium, voltage-gated K+ channels in ___ cells and contribute to the ___ phase of the action potential
autorhythmic and contractile; repolarization
In which septum is it normal to find openings in the adult?
atrioventricular septum
Which chamber initially receives blood from the systemic circuit?
right atrium
What is the correct order of valves through which the blood flows from the vena cava through the heart?
tricuspid, pulmonary semilunar, bicuspid, aortic semilunar
Which valve separates the left atrium from the left ventricle?
mitral
What is not an important factor when preventing the backflow of blood?
endocardium
The right ventricle pumps ___ blood into the ___ circulation
deoxygenated; pulmonary
In smooth muscle, Ca2+ for concentration comes from
extracellular fluid and the sarcoplasmic reticulum
True or False: Troponin plays the same role in smooth muscle contraction and skeletal muscle contraction
False
How do skeletal muscle fibers in the legs of a marathon runner differ from those of a sprinter who runs the 100-meter dash?
longer and thinner muscle fibers, mostly oxidative fibers, higher mitochondrial content, and less likely to fatigue
What is a potential energy source for an athlete sprinting the 40-yard dash?
phosphocreatine
Drug “X” inhibits acetylcholinesterase in the neuromuscular junction. What effect will drug “X” have on the membrane potential of the muscle fiber?
It would remain depolarized
When skeletal muscles lengthen, sarcomeres
lengthen
True or False: The length of the I band remains constant when the sarcomere shortens
FALSE
Acetylcholine receptor-channels allow diffusion of ___ when open
both Na+ and K+
In hyperkalemia (increased K+ conc.), the resting membrane potential of a muscle fiber is ___ negative and ___ likely to depolarize
less; more
What allows action potentials to move rapidly from the cell surface into the interior?
T-tubules
What characteristics differentiates skeletal muscle from both cardiac and smooth muscle?
multinucleated fibers and stimulated by somatic motor neurons
If a neuron releases norepinephrine, it is part of which division of the peripheral nervous system?
sympathetic
If a neuron releases acetylcholine, it is part of which division of the peripheral nervous system?
parasympathetic
Which physiological responses results from sympathetic action?
increase in heart rate
constriction of arterioles
stimulation of glycogenolysis
The two branches of the autonomic nervous system have which properties?
up-down regulation by tonic control
antagonistic control
chemical signals with different effects in different tissues
preservation of homeostasis
The sympathetic nervous system originates in the ___ region(s) of the spinal cord
thoracic and lumbar
The parasympathetic nervous system originates in the ___ region(s) of the spinal cord
sacral
The parasympathetic nervous system has ___ preganglionic and ___ postganglionic nerve fibers
long; short
The neurotransmitter in the synapse between pre- and postganglionic autonomic neurons is
acetylcholine
The neurotransmitter norephinephrine is made from
tyrosine
The receptor found on most parasympathetic target cells is
muscarinic cholinergic
True or False: The ligand ACh binds to receptor Nicotinic cholinergic
True
True or False: Ligand norephinephrine binds to receptor muscarinic choligernic
False
What is an example of a parasympathetic response?
Increased secretion og digestive enzymes
True or False: pH is a sensory stimuli for chemoreceptors
True
True or False: Osmolarity is a sensory stimuli for chemoreceptors
False
If you close your eyes and reach forward with one hand, you will know the position of that hand because of ___ activation
proprioceptor
Which receptors fire rapidly when first activated, then slowly and maintain their firing as long as the stimulus is present?
tonic receptors
What stimuli correspond for the taste of sweet?
GPRC, gustducin, glucose
What stimuli correspond for the taste of umami?
glutamate, GPRC, gustducin
Monosodium glutamate (MSG) used as a food additive stimulates which taste sensation?
umami
What directs sound into the ear?
the pinna
What separates the inner ear from the middle ear?
The oval window and round window
What structure in the middle ear amplifies soundwaves?
ear bones
What structure changes soundwaves into physical vibration?
the tympanic membrane
What is pitch?
frequency of sound and location on cochlear duct
what is loudness?
frequency of action potential (or amplitude)
True or False: Soundwaves change both frequency and amplitude
True
True or false: Sensory neuron action potentials for sound change amplitude
False
What is conductive hearing loss?
no transmission through either external or middle ear (maybe due to scar tissue, wax buildup, results in no sound down channel)
What is central hearing loss?
Damage to neural pathway between ear and cerebral cortex or damage to cortex itself (need cochlear implants)
What is sensorineural hearing loss?
Damage to structures of inner ear (hair damage)
Which of the otolith organs provides info for horizontal positioning?
Saccule
Which of the otolith organs provides info for vertical positioning?
Utricle
The organ of Corti sends electrical signals about sound to the brain. The perceived pitch of a sound is determined by the ___
location of the activated hair cells on the basilar membrane
Listening to loud music, especially through headphones, can eventually lead to irreversible ___ hearing loss
Sensorineural
When the cillary muscle is ___, the ligaments pull on and ___ the lens
relaxed; flatten
When ciliary muscle contracts, it ___ tension on the ligaments and the lens becomes more ____
releases; rounded
What is hyperopia?
far-sighted-ness (focal point behind retina)
What is myopia?
nearsightedness (focal point in front of retina)
What is presbyopia?
When there is a loss of felxibility in the eye
What is the ratio of cones to sensory neurons?
1:1
What is the ratio of rods to sensory neurons?
2-3:1
What type of cell is in both retinal and olfactory?
Bipolar cells
When is rhodospin inactive?
in darkness
A person with defective cones will have trouble
distinguishing colors
The loss of accomidation as we age is called
presbyopia
