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193 Cards in this Set
- Front
- Back
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what types of nervous systems do sea anemone have and what are the major functions |
nerve net |
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what types of nervous systems do flatworms have and what are their major functions |
eyespots, paired ganglia, ventral nerve cord |
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what types of nervous systems do earthworms have and what are their major functions |
brain, ventral nerve cord, segmental ganglion |
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what types of nervous systems do insects have and what are their major functions |
brain, eye, ventral nerve cord |
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what types of nervous systems do squid have and what are their major functions |
eye, brain, giant axon |
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what types of nervous system do frogs have and what are their major functions |
eye, brain, dorsal spinal cord, nerves |
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do all organisms have nervous systems? |
yes except for sponges |
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what types of nervous systems do humans have and what are their major functions |
CNS/PNS sensory neurons-receive and transmit information about an animals environment or internal physiological state interneurons-process and transmit info. to different regions motor neurons-create appropriate response (movement) or adjust internal physiological state circuits-formed by interconnected neurons |
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what is cephalization |
concentration of nervous system components at 1 end of the body |
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what advantages does cephalization have |
is an adaptation for forward locomotion and adaptation for predation |
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what are the major parts of a neuron |
cell body (soma) dendrites axon axon hillock synapses postsynaptic cell axon terminal |
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what does the cell body do |
contains the nucleus |
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what do the dendrites do |
highly branched processes where signals from axons of other cells are received |
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what does the axon do |
conducts electrical impulses away from the cell body |
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what does the axon hillock do |
last site in the soma where membrane potentials are summated before being transmitted to the axon. |
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what do synapses do |
small gap separating neurons |
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what does the postsynaptic cell do |
place for neurotransmitter molecules to bind |
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what does the axon terminal do |
transmit a neurotransmitter from one neuron to another |
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what are the major types of glial cells |
astrocytes schwann cells oligodendrocytes |
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what is the function of an astrocyte |
contribute to blood brain barrier (nutrition, development) |
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what is the function of a schwann cell |
works in the PNS |
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what is the function of an oligodendrocyte |
works in the CNS |
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How do thenumbers of glial cells compare to the number ofneurons |
glial cells are much more numerous than neurons in the human cortex but they're even everywhere else |
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what is the function of glial cells |
provide nutrition and physical support to neurons |
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Why is the voltage of neurons negative inside relative to theoutside |
because neurons create membrane potentials in order to allow specific ions to pass through |
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how is the resting potential maintained |
Potassium ions can cross through the membrane, while chloride and sodium ions have more problems crossing. the inside is more negatively charged than the outside |
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When we say that K has an equilibrium potential of -85 mV,what does that mean |
it means that at -85mV, the entire action potential is in equilibrium. so, when K is at -85, NA is at +68 mV |
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is the concentration of K higher inside or outside of the cell |
inside |
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is the concentration of Na higher inside or outside of the cell |
outside (na) |
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is the concentration of Cl higher inside or outside of the cell |
outside (Cl) |
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is the concentration of Ca higher inside or outside of the cell |
higher on the inside compared to NA |
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What types of channels are located in the dendrites, soma,axon hillock, axon, Node of Ranvier, internode, axon terminal? |
voltage-gated ion channels |
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what is threshold |
when the inward current carried by Na exceeds the outward current through K channels, creating positive feedback |
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What events take place in each phase of an action potential |
depolarization-voltage gated na+ channels open, voltage heads towards E[na] repolarization-na channels inactivate (and close) and K channels open more slowly hyperpolarization-open K channels start closing and NA channels start to de-inactivate |
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what channels are open when |
depolarization- Na+ channels open repolarization- K channels opening slowly hyper polarization- all channels closed |
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what is the refractory period and why is there one |
period before another AP can happen when neurons cannot fire another action potential, Na channels are inactivated and K channels are slowly closing |
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how do action potentials propagate down axons |
Na+ enters the axon charge spreads away from the sodium channels causing sections of nearby membrane to depolarize depolarization causes Na+ channels downstream to open, and positive feedback occurs |
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What determines the speed of an action potential |
depends on the diameter of the axon |
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What roledoes myelin play |
layers of myelin insulate the axon and as a result, action potentials "jump" from node to node, increasing the speed of conduction |
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what is saltatory conduction |
when AP jump from node to node |
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What are the steps in synaptic transmission at the synapse |
-begins with action potential conduction to the axon terminal -depolarization of the axon terminal opens voltage gated CA2+ channels -vesicles respond by fusing with the presynaptic membrane, releasing neurotransmitters -neurotransmitters bind with receptors on post synaptic cleft -after inactivation, neurotransmitters are reabsorbed into the presynaptic terminal and stored in vesicles until the next AP arrives |
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what is the role of calcium |
triggers the fusion of a synaptic vesicle with the pre synaptic membrane |
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What are the major neurotransmitters in the nervous system |
glutamate-primary excitatory neurotransmitters in CNS (learning/memory) GABA-primary inhibitory transmitter int eh CNS (spinal cord) Acetylcholine-excitatory at neuromuscular junctions, but inhibitory in other areas (heart) Monoamines- often modulatory and act via 2nd messengers, can be excitatory or inhibitory (G-proteins) |
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What is an EPSP |
excitatory post synaptic potentials- usually cause the membrane to depolarize, bringing the cell toward the threshold |
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what is an IPSP |
inhibitory post synaptic potential-usually cause the membrane to hyper polarize bringing the cell away from the threshold |
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what are spatial and temporal summation |
temporal- multiple EPSP's arrive quickly at a single synapse and set off an action potential spatial- single EPSP's at two or more different synapses set off an action potential |
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what part of the nervous system is the CNS |
brain and spinal cord |
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what part of the nervous system is the PNS |
cranial and spinal nerves |
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what is the difference between afferent and efferent |
Afferent=TOWARDS Cns efferent=AWAY from cns |
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what is the difference between the somatic and autonomic |
somatic=voluntary autonomic=involuntary |
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what is the sympathetic nervous system |
-fight/flight; arousal increased activity -sympathetic ganglia in the middle of the spinal cord -monitor and regulate internal functions of the body |
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what is the parasympathetic nervous system |
-rest/digest -cranial nerves/nerves from the lower section of the spinal cord -also monitor and regulate internal functions of the body |
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what is a reflex and how does it work |
-stretch receptor sends signal along sensory nerves -sensory neuron synapses with a motor neuron in spinal cord -motor neuron sends excitatory signal to same extensor muscle which contracts |
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How is sensory input transduced so that the nervoussystem can understand it |
the conversion of an external stimulus into an electrical signal by a sensory receptor cell |
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what are some types of sensory receptors |
chemoreceptors-perceive specific molecules or classes of molecules mechanoreceptors-respond to touch or pressure thermoreceptors-dtect temperature changes nocireceptors-sense pain or harmful stimuli photoreceptors-respond to wavelengths of light in the visible spectrum electroreceptors-detect electrical fields |
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What must transduction do to be effective |
must convey the strength of the signal carry info. about even weak stimuli when necessary convey the location of a signals source filter out unimportant background signals |
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what is lateral inhibition |
inhibition that neighboring neurons in brain pathways have on each other |
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when does adaptation occur |
adaptation to continuous stimuli reduces the firing rate over time |
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how does smell work |
receptors are coupled to G-proteins which activate cAMP to open a channel permeable to Na+, Ca2+, depolarizing the sensory neuron |
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why is the sense of smell in humans so poor |
bc half of these genes that express olfactory receptor proteins are mutated, making them nonfunctional |
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How can we detect so many differentodors |
bc each neuron only has 1 type of receptor, and each receptor protein binds a small set of molecules |
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what are the basic tastes |
sour sweet bitter salty savory (umami) |
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how are different tastes transduced |
saltiness= Na+ in food entering Na+ channels sourness=protons lower the pH the more sour a food tastes sweetness/bitterness=harder to pin down |
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why do many different foods taste bitter |
triggered by the binding of molecules to G protein-coupled receptors on the cell membranes of taste buds |
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how do hair cells transduce signals |
-pressure wave bends stereo cilia -potassium channels open -membrane depolarizes -calcium flows in -synaptic vesicles fuse -neurotransmitter is released |
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how do hair cells detect gravity and motion |
-hair cells sense water vibrations which may mean a predator/prey is near -the statolith moves and depresses hair cell stereocilia providing gravity detection |
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what is sound frequency |
the number of pressure waves per second |
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what is pitch |
differences in the sound frequency |
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How does the nervous system distinguish betweenloud and quiet sounds |
the amplitude of the waves determines loudness by producing larger vibrations that cause sterocilia to bend more |
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How is the duration of a sound signaled |
by the basilar membrane and hair cell activation |
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what are the major parts of the human ear |
outer ear middle ear inner ear |
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what is the function of the outer ear |
collects pressure waves in air and funnels them into the ear canal |
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what is the function of the middle ear |
ear ossicles (malleus, incus, stapes) vibrate against one another and amplify sound |
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what is the function of the inner ear |
responsible for balancing vestibular and auditory nerves |
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How does the nervous system distinguishdifferent sound frequencies |
sounds of different frequencies cause the basilar membrane to vibrate in specific spots along its length, resulting in the bending of hair cell steriocilia at these spots |
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what is the eye cup |
light hits photoreceprots |
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what is the compound eye |
good at detecting motion |
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what is the single lens eye |
focuses light on a retina and allows for a high degree of acuity (SQUID) |
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how do photoreceptors detect light |
retinal changes shape when it absorbs a photon of light, leading to a change in the opsin's conformation |
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what are the major parts of the eye |
sclera cornea iris pupil |
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what is the function of the sclera |
tough, white outermost layer |
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what is the function of the cornea |
transparent sheet of connective tissue; front part of the sclera, front of the eye |
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what is the function of the iris |
a colored, round muscle just behind the cornea. iris can contract or explained to control the amount of light entering the eye through the pupil |
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what is the function of the pupil |
the hole in the center of the iris |
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how are rods and cones different in what they detect |
rods=sensitive to dim light, but not to color cones=much less sensitive to faint light, but are stimulated by different wavelengths of light (colors) |
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how do we detect color |
brain distinguishes color by integrating information from the 3 types of ospins |
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do animals detect color the same way we do |
how well an animal can see color depends on the number of cones and the particular spins it has |
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why do we have a blind spot |
due to the axons of retinal ganglion cells that project to the brain via the optic nerve |
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what are the major parts of the brain |
forebrain midbrain hindbrain |
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function of the forebrain |
cerebral cortex, thalamus, hypothalamus |
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function of the midbrain |
brain stem |
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function of the hindbrain |
pons and medulla, cerebellum |
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what are the lobes of the cerebrum |
temporal frontal occipital parietal |
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function of the temporal lobe |
auditory perception, memory, speech |
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function of the parietal lobe |
movement, orientation, recognition, perceptuon |
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function of the frontal lobe |
reasoning, planning, speech, movement, emotions, problem solivng |
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function of the occipital lobe |
visual processing |
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How have lesion studies, imaging studies and stimulationduring surgery been used to map brain areas? what has been found? |
studies of people with brain damage, fMRI studies to map brain areas, electrical stimulation during brain surgery electrical stimulation of portions of the brain caused patients to report sensations of movement, temperature, touch |
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What part of the brain is critical for forming long-termmemories |
hippocampus |
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How does long-term potentiation work |
-discovered in the hippocampus -best model for how learning and memory work -found at synapses where glutamate is the neurotransmitter -results in an increase in the strength or weight of the synapse |
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what are the different types of muscle |
skeletal cardiac smooth |
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what is the structure of the skeletal muscle |
striated connect bones multinucleate long unbranched voluntary |
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what is a sarcomere |
a section between 2 discs; shorten when the muscle contracts and lengthen when the muscle is stretched |
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what makes up a sarcomere |
myosin and actin |
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how does the sliding filament model explain muscle contraction |
actin (THIN) filaments of muscle fibers slide past the myosin (THICK) filaments during muscle contraction while the 2 groups of filaments remain at relatively constant rates |
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how do actin and myosin interact during contraction? explain the cross bridge theory |
-myosin head binds ATP leading to detachment from actin -myosin head catalyzes the hydrolysis of ATP, forming ADP and Pi-> cocking the myosin head back -myosin head binds actin, forming a cross bridge |
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what role does ATP play |
ate must be present for myosin to relate from actin |
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How do action potentials lead to muscle contraction |
an action potential from a motor neuron arrives at the terminal leading to release of acetylcholine which diffuses across the cleft to bind to receptors on the motor neuron, opening channels causing a depolarization of of 10s of mV leading to an action potential in the muscle |
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what are t-tubules |
intersect with the sarcoplasmic reticulum and the depolarization there causes the release of calcium |
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what role does the sarcoplasmic reticulum play |
the sarcoplasmic reticulum regulates the release and intake of calcium into the muscle |
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what is the role of calcium in muscle contraction |
calcium binds to troponin which causes movement of tropomyosin exposing myosin binding sites on actin and resulting in the formation of cross bridges to produce contraction |
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what role do troponin and tropomyosin play in muscle contraction |
they help regulate muscle contraction troponin binds to actin and tropomyosin binds to troponin |
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how does a muscle relax |
calcium is pumped back into the sarcoplasmic reticulum which then breaks the bonds between actin and myosin. actin and myosin return to their original state causing relaxation to occur |
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What happens if ACh receptors are blocked or ifcalcium pumps in the SR are blocked? |
if calcium pumps are blocked, the muscle will never be able to relax if ACh receptors are blocked, the muscle will never be able to contract |
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how is smooth muscle contraction different |
-smooth muscle lacks the troponin-tropomyosin mechanism for regulating contraction -smooth muscle activated by the autonomic nervous system, muscle stretch, hormones or other factors. with activation: 1. calcium enters via voltage and stretch receptor calcium channels and calcium is released from the SR 2. myosin kinase phosphorylates the myosin heads 3. the phosphorylated myosin heads bind actin and begin the cross-bridge cycle 4. a phosphate dephosphorylates the myosin heads, myosin unbinds and the muscle relaxes |
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What determines the sarcomere length that givesthe maximum contraction |
1. changes in overlap between myosin and actin affect the number of cross-bridges and thus the force 2. maximal force at an intermediate sarcomere length (~2.3 micrometers) |
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how are muscle force and shortening velocity related |
INVERSELY RELATED maximum isometric force occurs at intermediate sarcomere lengths where the greatest number of cross-bridges can form when a muscle is actively lengthened, it generates increased force (lengthening contraction) |
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what is a lengthening contraction |
when a muscle is actively lengthened, it generates increased force |
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Why do we need antagonistic pairs of muscles, suchas extensors and flexors |
muscles generate force only by pulling on the skeleton, so muscles are arranged in antagonist pairs -triceps shorten to extend -biceps shorten to flex |
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what is a twitch |
a contraction with a delay in force |
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what is a tetanus |
muscle force sums to higher levels when action potentials stimulate the muscle at higher rates, reaching a tetanus |
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what is a motor unit |
a motor neuron and the population of muscle fibers (cells) it activates |
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what is a slow twitch muscle |
-red muscle -many mitochondria -well supplied with blood vessels -use aerobic respiration -maximum tension is low, develops more slowly, but is highly resistant to fatigue -long distance runners, swimmers, cyclists |
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what is a fast twitch muscle |
-white muscle -few mitochondria -little myoglobin -rely on anaerobic glycolysis -has high atpase activity -develop maximum tension rapidly with great tension, but fatigue easily -cannot replenish ATP fast enough to sustain contractions -weight lifters, sprinters |
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what are the 3 types of skeletons |
hydrostatic skeletons exoskeletons endoskeletons |
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what is an exoskeleton |
hard hollow structures that envelope the body hardened outer structure to which muscles attach internally, provides protection and helps prevent dehydration. hard to repair and requires molting for growth |
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what is an endoskeleton |
hard structures inside the body composed of connective tissues (cartilage and bone) |
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what are tendons |
connects muscle to bone |
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what are ligaments |
connects bone to bone |
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what is bone |
made by osteoblasts, cells that secrete calcium phosphate with small amounts of calcium carbonate and collagen fibers to form a hard extracellular matrix |
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what is cartilage |
made up of cells scattered in a gelatinous matrix of polysaccharides and protein fibers. provides padding between bones |
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how are bones formed |
1. axial skeletons (Skull and ribs) precursor cells differentiate into osteoblasts which immediately produce bone (slow process) 2. most other bones are formed as cartilage first (endochondrial ossification) |
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what are osteoclasts |
remove bone from the inside |
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what are osteoblasts |
deposit new bone on the outside |
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what are the major types of joints |
ball and socket hinge |
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what range of motion do ball and socket joints provide |
shoulder/hip broader range of motion (3D) allow motion along all 3 axes |
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what range of motion do hinge joints provide |
elbow, knee primarily flexion and extensions limit motion to 1 primary axis |
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how do bones grow |
as cartilage is further transformed into bone, new cartilage continues to be added at the growth plate, causing the bone to grow in length |
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how are bones repaired |
repair of damaged endoskeleton can be done by osteoblasts and osteoclasts |
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why do we need to breathe |
to sustain cellular respiration -O2 is needed to burn carbs, lipids, and proteins to make ATP |
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what is Fick's law |
O2 and CO2 can diffuse in the greatest amounts when a) the surface area for gas exchange is large b) the respiratory surface is extremely thin c) the partial pressure gradient of the gas across the surface is large |
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How can we compute the partial pressure of oxygenat sea level |
atmospheric pressure at sea level is 760 mmHg -the sum of the partial pressures of a mixture of gases equals the total atmospheric pressure |
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how does partial pressure change with altitude |
as altitude increases, partial pressure decreases |
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How does the proportion of oxygen in air changewith altitude |
the percentage of oxygen in the air stays the same higher altitudes does deliver less oxygen/breath |
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how do gills work |
they are outgrowths of the body surface or throat used for gas exchange in aquatic animals |
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what factors make gills efficient |
they present an extremely large surface area for oxygen to diffuse across an extremely thin epithelium |
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how do fish breathe |
through its gills with a COUNTERcurrent flow |
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How does countercurrent exchange work tomaximize the amount of oxygen taken up by gills |
contracts O2, it ensures that the difference in the amount of O2 and CO2 in water vs. blood is large over the entire respiratory surface |
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how does the tracheae work in insects |
they form an expense system of tubes located well within the insect body |
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what are spiracles |
an external respiratory opening |
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How might muscle activity ventilate tracheae |
humans and other mammals ventilate their lungs by increasing their lung volume by expanding their thoracic cavity to draw oxygen rich air into the lungs and reduce their lung volume to expire oxygen-poor air from the lungs |
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what is tidal ventilation |
intercostal muscles and the diaphragm contract, the net effect is that the chest cavity becomes larger which reduces air pressure in the lungs |
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Why is the Po2 only 100 mm inour lung when air Po2 is 160 |
because once the diaphragm contracts, the diaphragm moves down and the ribs move out. this lowers the negative pressure in the chest cavity. as the pressure surrounding the lungs drops, the lungs expand and air flows in along the pressure gradient |
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What is a typical ventilation rate at rest |
12-20 breaths per minute |
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What are the parts of the human lung |
trachea bronchi bronchioles alveoli |
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where is gas exchanged |
alveoli |
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how is gas exchanged |
air passes through the larynx larynx to trachea trachea into bronchi bronchi into bronchioles bronchioles into alveoli which greatly increase the surface area for gas exchange |
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How does the bird respiratory system work |
1. draws oxygen-rich air into posterior air sacs 2. exhalation moves fresh air into lung 3. second inhalation moves stale oxygen depleted air from lung into anterior air sacs 4. second exhalation moves air out of anterior air sacs |
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Whatadvantages does this system have |
bird lungs are rigid (don't inflate or deflate) air flow is unidirectional, allowing for a larger (P2-P1) birds are able to extract enough O2 for extremely long flights and flights at high elevation where PO2 is low |
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How is the bird respiratory system different from ours |
-birds have a continuous supply of fresh air in both inhalation and exhalation -birds have air sacs -birds do not have a diaphragm -bird lungs do not contract or expand |
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how is breathing rate controlled |
by chemoreceptors in the medullary respiratory system in the brain stem set the respiratory rhythm |
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what signal is sensed |
sensors detect drop in O2 levels and an increase in Co2 levels |
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what part of the nervous system is the effector |
the diaphragm and other respiratory muscles |
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how does it generate a response? |
diaphragm/muscles contract more frequently and more strongly |
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Why do we need a molecule like hemoglobin to transportO2 |
because hemoglobin is able to bind to the oxygen molecules
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How does hemoglobin transport O2 |
by attaching each iron ion to an individual oxygen molecule |
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What shape does the oxygen-hemoglobin equilibrium curvehave |
increasing in a backwards s shape |
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Why does it have this shape |
because in the middle of the curve, small increases (or decreases) in Po2 result in large increases (or decreases) in hemoglobin saturation |
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How do temperature and pH affect oxygen binding tohemoglobin |
by the bohr shift |
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What is the Bohr shift |
decreases in pH and increases in temperature alter hemoglobin conformation to make it more likely to release o2 at all Po2 levels |
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How does fetal hemoglobin differ from hemoglobin of themother |
the fetus's hemoglobin allows the fetus to take in O2 from the mothers circulation |
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why is this a good thing |
this is a good thing because the fetus is able to get its supply of oxygen |
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What types of animals typically have open circulatory systems |
insects and many mollusks including clams |
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what are the characteristics of open circulatory systems |
-blood flows through a vessel with muscular thickenings that act as a pump -blood empties into an open body cavity to supply the tissues with nutrients and is returned to the circulation |
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what are the characteristics of a closed circulatory system |
-blood flows through connected blood vessels -pumped by muscular hearts -the blood flows through vessels to supply tissues with nutrients |
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what types of animals have closed circulatory systems |
larger animals, vertebrates, earthworms, squid, octopus |
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what is one advantage of an open circulatory system |
molecules do not have to diffuse across blood vessels to get to tissues |
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what is one advantage of a closed circulatory system |
blood flow can be directed in a precise way. regulatory systems can shun blood to specific vessels and thus to specific locations |
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How do we maintain blood flow through the circuitand still have gas exchange |
-blood leaves arteries with high flow rate because of low resistance due to large diameter vessels -number of capillaries is large, making total cross sectional are large -this effects the increased resistance to maintain blood flow through the circuit |
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what is an artery |
-large, high pressure vessels that carry blood away from the heart -walls are tough/thick, containing muscle and elastic layers composed of elastin and collagen |
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what are veins |
-carry deoxygenated blood back to the heart. -because blood pressure is relatively low, veins have much thinner walls and much larger interior diameters than arteries |
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what are capillaries |
-smalles, thinnest vessels -walls are 1 cell layer thick, allowing blood and other tissues in dense networks called capillary beds |
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what is hemolymph |
an invertebrates equivalent to blood |
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what is lymph |
a colorless fluid containing white blood cells, that bathes the tissues and drains through the lymphatic system into the bloodstream |
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where does lymph come from |
from blood vessels that flow throughout the body |
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where does lymph go |
back into the blood |
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How does blood flow in the fish circulatory system |
1. deoxygenated blood enters the atrium from a main vein and is pumped into the ventricle 2. deoxygenated blood is pumped from the ventricle into a main artery |
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what is a disadvantage of the fish circulatory system |
much of the blood pressure is lost moving across small capillaries in the gills. This limits the flow of oxygenated blood to body tissues |
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How does blood flow in the mammalian circulatorysystem |
1. deoxygenated blood enters the right atrium from the inferior and superior venae cavae 2.deoxygenated blood passes through the right AV valve and enters the right ventricle 3. deoxygenated blood is pumped into the pulmonary arteries through the pulmonary valve 4. oxygenated blood returns from the lungs to the left atrium 5. oxygenated blood enters the left ventricle through the left ventricle through the left AV valve 6. oxygenated blood is pumped by the left ventricle through the aortic valve into the systemic circulation |
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in what parts of the heart is blood oxygenated |
left atrium left ventricle |
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what are the 2 phases of the cardiac cycle |
pulmonary and systemic circuit |
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what happens during the pulmonary circuit |
1. oxygen depleted blood enters the right atrium 2. when the right atrium contracts, the deoxygenated blood moves through an AV valve into right ventricle 3. right ventricle contracts and sends deoxygenated blood through the pulmonary valve to the lungs via pulmonary arteries 4. once blood has circulated through the capillary beds in the lungs and alveoli and become oxygenated, it returns to the heart to the left atrium |
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what happens during the systemic circuit |
1.left atrium contracts sending oxygenated blood through the left AV valve to the left ventricle 2. left ventricle contracts sending oxygenated blood through the aortic valve |
