MCB 32 MT #2
What do thermoreceptors sense?
Temperature
Which of the following will bring the membrane potential closer to the action potential threshold? - Decreased extracellular K+ concentration -Increased number of voltage-gated Na+ channels in the axon hillock -Increased permeability for K+ -Temporal summation with an excitatory synapse
Temporal summation with an excitatory synapse
An action potential was recorded from a neuron before [the control] and after the addition of an ion channel inhibitor. The action potentials are shown below, one on top of the other (but they were recorded at different times). Pick the answer that most likely describes what the inhibitor does. - The inhibitor blocks K+ leak channels -The inhibitor partially blocks voltage-gated K+ channels -The inhibitor partially blocks voltage-gated Na+ channels -The inhibitor blocks Na+ leak channels
The inhibitor partially blocks voltage-gated K+ channels
Imagine you have a cell with a membrane potential (Vm) = - 50 mV. The membrane is permeable to the cation X+, which has an equilibrium potential (Ex) = - 30 mV. Which direction will X+ go across the membrane under these conditions? - The same number of X+ will go in as out of the cell -The net movement of X+ will be into the cell -The net movement of X+ will be out of the cell
The net movement of X+ will be into the cell
The ATP that comes from creatine phosphate will - be used by voltage-gated Na+ channels - power the release of vesicles from the motor neuron - bind to myosin and power the crossbridge cycle - bind troponin to expose myosin binding sites
bind to myosin and power the crossbridge cycle
When heat opens TRP channels, we call this process: - sensory coding - sensory transduction - sensory transmission - integration
sensory transduction
Clicker question The diagram on the right shows the hormonal pathway regulating the release of sex hormones. It is very similar to the cortisol pathway we learned about last time. Where do you think you would find a progesterone receptor? A) Inside cells of the hypothalamus B) On the membrane of cells in the gonads C) On the membrane of cells in the anterior pituitary D) On the membrane of cells in the hypothalamus
A) Inside cells of the hypothalamus
Clicker question Which direction will Ca+2 go if the cell becomes more permeable to Ca+2? (Vm = -90 mV, ECa = 122 mV) A) Into the cell B) Out of the cell C) Equal amount going in as going out D) No movement across membrane
A) Into the cell
The typical concentrations of potassium (K+) are shown inside and outside of a neuron. If the membrane were permeable to K+, then the net movement of K+ would be _________ the cell, and the inside of the cell would get more ________________. A) Out of; negative B) Out of; positive C) Into; negative D) Into; positive
A) Out of; negative
The typical concentrations of sodium (Na+) are shown inside and outside of a neuron. What is the equilibrium potential for Na+? Think about which way Na+ would move across the membrane if there were open ion channels for it. A) Positive equilibrium potential B) Negative equilibrium potential C) Equilibrium potential = 0
A) Positive equilibrium potential
Which fiber type would be most prominent in a marathon runner's leg muscles? A)Slow oxidative B)Fast oxidative C)Fast glycolytic
A) Slow oxidative
Where does the blood come from that is released during menstruation? A) Uterine lining B) Ovaries C) Fallopian tube D) Vagina
A) Uterine lining
Which of the following structures of an autonomic neuron is NOT located within the ganglion? A) the cell body of preganglionic neurons B) the axon terminal of preganglionic neurons C) the synapse between pre- and postganglionic neurons D) the cell body of postganglionic neurons E) the dendrites of postganglionic neurons
A) the cell body of preganglionic neurons
Metabotropic receptor-induced gating of ion channels requires more time to occur because of which of the following? A) their gating is linked to a G protein B) the channels are slower to open C) intracellular calcium must increase before those channels will open D) ion channels linked to metabotropic receptors must move to the membrane before gating
A) their gating is linked to a G protein
Which of the following is NOT physically located in the central nervous system? A)Dendrites of sensory neuron B)Dendrites of efferent neuron C)Axon terminal of afferent neuron D)Axon terminal of interneuron E)Cell body of efferent neuron
A)Dendrites of sensory neuron
Ex = -60 mV If ion channels for X- opened in this cell, which direction would X-go across the membrane? A)Into the cell B)Out of the cell C)Same amount into the cell as out of the cell D)No ion movement across membrane
A)Into the cell
What will happen if a ligand-gated ion channel opens that is permeable to all cations (Na+, K+ and Ca+2)? A)Postsynaptic cell depolarizes B)Postsynaptic cell hyperpolarizes C)No change in membrane potential
A)Postsynaptic cell depolarizes
Clicker question If a patient has a right hemisection of their spinal cord about halfway down, they will be paralyzed in their ____________ and proprioception will be impaired in their _____________. A)Right leg; right leg B)Right leg; left leg C)Left leg, right leg D)Left leg; left leg
A)Right leg; right leg
Which of the following substances do you think could get through the blood brain barrier? (There is more than one correct answer) A) Glucose B) Oxygen C) Red blood cells D) Glycogen E) Cortisol
A, B, E
The role(s) of ATP in muscle contraction include: A) ATP hydrolysis is necessary for myosin to form a crossbridge with actin B) Binding to the troponin complex to expose myosin-binding sites C) Binding to myosin to break an actin-myosin crossbridge D) The energy from ATP is used to pump Ca+2 into the sarcoplasmic reticulum E) Binding to receptors on the muscle fiber to depolarize the membrane and trigger an action potential
A,C,D
Women have small amounts of testosterone and men have small amounts of progesterone and estrogen. Obviously these hormones must be coming from other places besides the ovaries and testes. The sex hormones are also made in one other location in the body. Think about the chemical nature of these hormones and how they are synthesized. Then pick one logical location where they are also produced. -Adrenal cortex -Anterior pituitary -Posterior pituitary -Hypothalamus
Adrenal Cortex
What is a consequence of the refractory period in axons? A) The frequency of action potentials is always the same B) Action potential amplitudes cannot summate C) The brain is only active every 10-15ms D) It will take 10-15ms for an action potential to travel down an axon to the terminal
B) Action potential amplitudes cannot summate
When does ovulation (egg release) occur during the menstrual cycle? A) Start of menstruation (period) B) Around 14 days after the start of menstruation C) At the end of menstruation D) Around 7 days after the start of menstruation
B) Around 14 days after the start of menstruation
What is the role of astrocytes in the blood brain barrier? - Astrocytes help insulate the axons -Astrocytes allow some molecules into the brain via gap junctions -Astrocytes provide an extra layer that molecules must go through in order to enter the brain -Astrocytes wrap around blood vessels and only allow lipopobic molecules into the brain
Astrocytes provide an extra layer that molecules must go through in order to enter the brain
Which of the following statements about the Na+ equilibrium potential is correct? -At this potential there is more Na+ inside the cell than outside -At this potential there will be as many Na+ ions entering the cell as leaving the cell -At this potential ion movement across the membrane stops -At this potential there will be a net force on potassium (K+) pointing into the cell
At this potential there will be as many Na+ ions entering the cell as leaving the cell
True/false: All people have the same perception of the external environment.
False, different sensitivity levels among different people.
Clicker question Think back to what you learned about intercellular signaling... In the dendrites, there are neurotransmitter receptors that are either ligand-gated ion channels or G-protein coupled receptors (GPCR). Choose the correct statement about these receptors. A) Ligand-gated ion channels are not selective for particular ions (all ions can go through) B) Ligand-gated channels lead to a faster response than GPCRs. C) GPCRs are enzymes that phosphorylate other enzymes inside the cell D) GPCRs are ion channels
B) Ligand-gated channels lead to a faster response than GPCRs.
Which lobe is the primary somatosensory cortex in? A) Occipital B) Parietal C) Temporal D) Frontal E) Hippocampal
B) Parietal
1 ms after voltage-gated Na+ channels open, they inactivate for several milliseconds. What is the consequence of inactivation? A) Na+ will flow out of the neuron while the channels are inactivated B) The neuron cannot fire another action potential until the voltage- gated Na+ channels are reset back to the resting state C) The neuron will rely on K+ going into the cell to initiate another action potential D) The equilibrium potential for Na+ will change and become more negative
B) The neuron cannot fire another action potential until the voltage- gated Na+ channels are reset back to the resting state
Sensory neurons are ____________ neurons and their cell bodies are in the _____________. A) afferent; ventral root B) afferent; dorsal root ganglion C) efferent; spinal cord D) efferent; brain
B) afferent; dorsal root ganglion
What is the physiological explanation for tetanus? A)Action potentials are at such a fast frequency that they summate B)Myosin power stroke is more forceful C)Next stimulus occurs before Ca+2 is pumped back into sarcoplasmic reticulum, so more Ca+2 in the cytoplasm D)More crossbridges are forming
C/D
3) During skeletal muscle contraction A) the thick and thin filaments get shorter B) the Z lines in the sarcomere get closer together C) Ca+2 binds myosin D) the graded potential causes voltage-gated Ca+2 channels to open on the membrane E) myosin forms crossbridges with tropomyosin
B) the Z lines in the sarcomere get closer together
Which of the following would most likely cause this graded potential? A)GABA receptor agonist B)GABA receptor antagonist C)Glutamate receptor agonist D)Release of glutamate into synaptic cleft
B)GABA receptor antagonist
During this reflex, which muscles in the right leg are contracting? A)Only quads contract B)Only hamstrings contract C)Quads and hamstrings contract D)Neither muscle contracts
B)Only hamstrings contract Quads are relaxed
What role does Ca+2 play in muscle contraction? A) Activates myosin ATPase activity (hydrolyzes ATP) B) Release of acetylcholine from motor neuron C) Exposes myosin binding sites on actin D) Causes graded potential E) Binds myosin head during power stroke
B/C
There are three main types of muscle fibers, which have different physical and functional properties. Which of the following muscle fibers would be most likely to fatigue quickly? Fatigue = muscle cannot maintain a long-term constant force A) Muscle fibers with a lot of nuclei B) Muscle fibers that do anaerobic respiration most of the time C) Muscle fibers without a lot of creatine D) Muscle fibers with a low concentration of mitochondria E) Muscle fibers that have a large diameter
B/D/E
Cutting the sympathetic nerve to the face seems kind of drastic. The first step in treating someone medically with excessive blushing might be to try a medication. Which medication would most likely inhibit blushing? - Beta adrenergic agonist - Muscarinic antagonist - Beta blocker (beta adrenergic antagonist) - Inhibitor of norepinephrine reuptake
Beta blocker (beta adrenergic antagonist)
What would be a good treatment for myasthenia gravis? A) Nicotinic AChR antagonist B) Muscarinic AChR agonist C) Acetylcholine esterase inhibitor D) Beta blocker E) Albuterol (beta adrenergic agonist)
C) Acetylcholine esterase inhibitor Slows breakdown of Ach
Neurons in the efferent nervous system have their cell bodies in the __________________ and their axon terminals in the __________________. A) periphery; ventral root B) periphery; spinal cord C) CNS; periphery D) Ventral root; CNS E) Spinal cord; brain
C) CNS; periphery
Which of these pairings between brain structure and function is incorrect? A) Thalamus - relay station for sensory B) Medulla oblongata - regulate breathing rate C) Cerebellum - regulation of homeostasis D) Ventricle - holds cerebrospinal fluid E) Midbrain - orienting head to sounds
C) Cerebellum - regulation of homeostasis Cerebellum controls motor movements.
2) True/False: High levels of estrogen in the late follicular phase help prepare the uterus for menstruation.
False, it helps prepare the body for ovulation
Which of the following statements is FALSE? A) Graded potentials can sum over time but action potentials cannot. B) Graded potentials do not have refractory periods, but action potentials do. C) Graded potentials and action potentials are all-or-none. D) Graded potentials and action potentials are caused by ions moving through channels. E) Graded potentials and action potentials can change the membrane potential of adjacent areas of the membrane.
C) Graded potentials and action potentials are all-or-none. Only action potentials are all-or-none.
Clicker question Why is epinephrine considered to be a neurohormone? A) It is released from the axon of a postganglionic neuron B) It is released by an endocrine cell in the adrenal gland C) It is released by a modified postganglionic neuron and travels in the blood D) It is released by the same cells that release norepinephrine
C) It is released by a modified postganglionic neuron and travels in the blood.
2) Which of the following pathways to the somatosensory cortex is correct? Note: each name indicates the location of a synapse. A) Mechanoreceptor à spinal cord à thalamus à somatosensory cortex B) Nociceptor à medulla à somatosensory cortex C) Mechanoreceptor à medulla à thalamus à somatosensory cortex D) Thermoreceptor à spinal cord à medulla à somatosensory cortex E) Nociceptor à spinal cord à medulla à somatosensory cortex
C) Mechanoreceptor à medulla à thalamus à somatosensory cortex
Think back to what you learned about intercellular signaling... The receptors for neurotransmitters are found A) On the membrane of the axon B) Inside the neuron (intracellular receptor) C) On the membrane of the dendrites D) In the nodes of Ranvier
C) On the membrane of the dendrites
The menstrual cycle is controlled by female sex hormones. When is estrogen at its highest concentration? A) During menstruation B) Right before menstruation C) Right before ovulation D) After ovulation
C) Right before ovulation Positive feedback occurs with Luteinizing hormone (LH)
1) What are sensory receptors that respond to tissue-damaging stimuli or stimuli that have the potential to damage tissue called? A) thermoreceptors B) proprioceptors C) nociceptors D) mechanoreceptors E) stretch receptors
C) nociceptors
Muscles of the legs and back that help us maintain posture tend to have a high proportion of what fiber type? A) fast oxidative B) slow glycolytic C) slow oxidative D) fast glycolytic E) fast and slow glycolytic
C) slow oxidative
How do ions get across the plasma membrane? A)Simple diffusion B)Transporters C)Channels D)GPCRs E)Intracellular receptors
C)Channels
Clicker question If Vm = +20 mV in a neuron (with normal ion gradients), which of the following statements about K+ is correct? A)K+ will go across the membrane by simple diffusion B)The electrical force is pointing into the cell C)The concentration force is pointing out of the cell D)K+ will predominantly enter the cell if K+ ion channels are open
C)The concentration force is pointing out of the cell
During a muscle contraction A)The actin filaments get shorter B)The myosin filaments get shorter C)The sarcomere gets shorter D)The motor neuron gets shorter E)The sarcoplasmic reticulum gets shorter
C)The sarcomere gets shorter
Given: Vm = -70 mV, EK = -90 mV, ENa = +60 mV, ECa = +122 mV Remember: ions "want" the cell to be at their equilibrium potential. a) Which direction will Ca+2 go if the cell becomes more permeable to Ca+2? Explain.
Ca2+ goes in to make the E closer to 122 mV
Parietal lobe function?
Contains primary somatosensory cortex
Pons function
Controls breathing
1) Which of the following statements about sodium is FALSE? A) There is a chemical force driving sodium ions into the cell. B) At the resting membrane potential, there is an electrical force driving sodium ions into the cell. C) At the sodium equilibrium potential, there is an electrical force driving sodium ions out of the cell. D) At the potassium equilibrium potential, there is an electrical force driving sodium ions out of the cell. E) At the sodium equilibrium potential, the electrochemical force for sodium movement across the plasma membrane is zero.
D) At the potassium equilibrium potential, there is an electrical force driving sodium ions out of the cell. Electrical force is driving sodium ions in.
There are a number of diseases that cause demyelination of axons (like multiple sclerosis). What defect would you expect in someone with demyelinated ventral root neurons? A) Leaky blood brain barrier B) Impaired vision C) Inability to sense pain D) Impaired/slow limb movement
D) Impaired/slow limb movement
The typical concentrations of Na+ and Chloride (Cl-) are shown inside and outside of a neuron. The membrane potential of this neuron is -70mV. Fill in the blanks: The electrical force on Na+ is pointing ___________ the cell. The electrical force on Cl- is pointing ______________ the cell. A) Out of the cell; out of the cell B) Into the cell; into the cell C) Out of the cell; into the cell D) Into the cell; out of the cell
D) Into the cell; out of the cell
2) If the resting membrane potential is equal to chloride's equilibrium potential, in which direction will chloride ions move if chloride channels open while the cell remains at resting membrane potential? A) inward B) outward C) No ions will move through the channel. D) Ions will move equally in both directions. E) Three chloride ions will move out for every two chloride ions that move in.
D) Ions will move equally in both directions. The cell is at equilibrium potential!!!
Think back to what you learned about intercellular signaling... Neurotransmitters are all ________________ and are released from neurons by __________________. A) Lipophilic; simple diffusion B) Lipophobic; simple diffusion C) Lipophilic; exocytosis D) Lipophobic; exocytosis
D) Lipophobic; exocytosis
2) Which one of the following steps of muscle contraction does NOT directly require ATP? A) Pumping Ca+2 into the sarcoplasmic reticulum B) Maintaining the appropriate Na+ and K+ ion gradients C) Myosin head releases actin D) Moving tropomyosin off the myosin binding sites
D) Moving tropomyosin off the myosin binding sites
The receptors in skeletal muscle are: A) Nicotinic acetylcholine receptors that cause a hyperpolarizing or depolarizing graded potential B) Muscarinic acetylcholine receptors that cause a depolarizing graded potential C) Muscarinic acetylcholine receptors that activate a G-protein that opens Na+ channels D) Nicotinic acetylcholine receptors that are cation-selective ion channels
D) Nicotinic acetylcholine receptors that are cation-selective ion channels
What do you expect from a patient with damage to the right side of the spinal cord? A) No touch sensation anywhere on the left side of the body B) No pain sensation on the right side below the lesion site C) No temperature sensation anywhere on the left side of the body D) No touch sensation on the right side below the lesion site E) No temperature sensation anywhere on the right side of the body
D) No touch sensation on the right side below the lesion site
Which one of the following structures is correctly paired with its function? A) Seminiferous tubules - release LH B) Prostate gland - release of urine C) Anterior pituitary - release testosterone D) Seminiferous tubules - sperm production E) Vas deferens - semen production
D) Seminiferous tubules - sperm production
What path do sperm take through the male reproductive system? A) Seminal vesicles à seminiferous tubules à vas deferens à urethra B) Seminiferous tubules à ejaculatory duct à vas deferens à epididymis à urethra C) Prostate à vas deferens à urethra D) Seminiferous tubules à epididymis à vas deferens à ejaculatory duct à urethra
D) Seminiferous tubules à epididymis à vas deferens à ejaculatory duct à urethra
Curare is an antagonist of nAChRs in muscles. What will happen to an animal that has been hit with an arrow covered in curare? A) Muscles will be paralyzed B) Autoimmune response will destroy muscles C) Muscles will contract uncontrollably D) The motor neurons will stop releasing ACh E) Acetylcholinesterase will stop functioning
D) The motor neurons will stop releasing ACh
Which of the following statements about end-plate potentials (the potential change in the muscle) is FALSE? A) They are graded potentials. B) They are always depolarizations. C) They are almost always of sufficient magnitude to generate an action potential. D) They are a result of acetylcholine binding to muscarinic cholinergic receptors. E) They are terminated by removal of acetylcholine from the synaptic cleft.
D) They are a result of acetylcholine binding to muscarinic cholinergic receptors.
2) If, under resting conditions, the membrane is much more permeable to sodium than potassium, what would happen to the resting membrane potential? A) be altered very little B) become more negative C) approach potassium's equilibrium potential D) approach sodium's equilibrium potential E) approach chloride's equilibrium potential
D) approach sodium's equilibrium potential
The opening of a cation channel that allows both Na+ and K+ to move through will cause the membrane to ________ because of the ________. A) hyperpolarize : greater K+ electrochemical gradient as compared with Na+ B) hyperpolarize : greater Na+ electrochemical gradient as compared with K+ C) depolarize : greater K+ electrochemical gradient as compared with Na+ D) depolarize : greater Na+ electrochemical gradient as compared with K+ E) not change : same electrochemical gradient for K+ and Na+
D) depolarize : greater Na+ electrochemical gradient as compared with K+
Which of the following does NOT have nicotinic cholinergic receptors? A) skeletal muscle cells B) parasympathetic postganglionic neuron dendrites C) sympathetic postganglionic neuron dendrites D) effector organs for the parasympathetic nervous system E) chromaffin cells
D) effector organs for the parasympathetic nervous system
1) Which of the following does NOT influence the force generated by an individual muscle fiber? A) frequency of stimulation B) fiber diameter C) fiber length D) recruitment E) summation
D) recruitment
Clicker question The postganglionic neurons are causing complex changes in the target organs/tissues, not just graded potentials. What type of receptors are likely on the target cells? A) Enzyme-linked receptor B) Ionotropic receptor C) Intracellular receptor D) Metabotropic receptor E) GPCRs
D/E
Given what you have learned about brain anatomy, which part of the brain is likely to control the autonomic nervous system? A) Thalamus B) Frontal lobe C) Cerebellum D) Medulla oblongata E) Hypothalamus
D/E
What directly causes menstruation? - Decrease of progesterone and estrogen levels -Inhibition of estrogen by FSH/LH -Ovulation -Formation of the corpus luteum
Decrease of progesterone and estrogen levels
Review of cortisol signaling Which of the following statements is true? A) Cortisol is an enzyme that helps breakdown proteins B) Cortisol is an enzyme that helps breakdown glucose C) Cortisol receptors are enzymes that catalyze protein synthesis D) Cortisol is a membrane transporter for glucose E) Enzymes involved in breaking down proteins get activated/expressed when cortisol binds the cortisol receptor in muscles
E) Enzymes involved in breaking down proteins get activated/expressed when cortisol binds the cortisol receptor in muscles
Touch activates mechanoreceptors. What is the likely response in mechanoreceptors during a touch stimulus? A) K+ channel opens B) Na+ channel closes C) Increased glucose transporters to membrane D) Increased gene expression E) Na+ channel opens
E) Na+ channel opens All stimuli cause a Na+ channel to open, so a response can be generated
There are actually two forms of blushing: 1) Fast facial blushing is treated well with the sympathectomy 2) Slow blotchy blushing that occurs mostly on the neck and shoulders is not affected by the sympathectomy. This type of blushing is caused by epinephrine signaling. Why does sympathectomy have no effect on the slow type of blushing? - Epinephrine is released from the adrenal medulla, which would still function if the facial nerves are cut - Epinephrine is part of the parasympathetic nervous system, not the sympathetic - The sympathectomy spares the postganglionic neurons that release epinephrine directly onto target cells - Epinephrine is released from the anterior pituitary, which would not be damaged during sympathectomy
Epinephrine is released from the adrenal medulla, which would still function if the facial nerves are cut
True/False: The composition of cerebrospinal fluid is identical to plasma.
FALSE
Clicker question True or False? A stronger stimulus will cause a larger action potential in the sensory neuron. A)True B)False
FALSE, action potential is all or nothing.
Lecture 9 is about the electrical signal in neurons and this can be a difficult subject to understand. To prepare for the next class, please watch this animation: http://sites.sinauer.com/neuroscience5e/animations02.01.html (Links to an external site.)If you cannot watch the video, then you can look up this information in the textbook (figure 7.10). Which of the following statements best describes the forces that are acting on ions across the plasma membrane of a resting neuron (which is negative inside)? -There is a diffusion (or chemical) force on K+ to move it into the cell -For K+ ions, there is an electrical force attracting the ions into the cell -There is an electrical force acting on the intracellular protein anions, keeping them inside of the cell -There is a diffusion (or chemical) force acting on Na+ to move it out of the cell
For K+ ions, there is an electrical force attracting the ions into the cell
What are the four cerebral lobes?
Frontal, Parietal(contains somatosensory cortex), Occipital, TEMPORAL
Which type of medicine would be the most useful for someone with epilepsy in order to stop seizures? - Glutamate receptor agonist - GABA receptor agonist - Inhibitor of glutamate transporter - GABA receptor antagonist
GABA receptor agonist
Which of the following is true of both the female and male human reproductive systems? -There is positive feedback onto the anterior pituitary -LH and FSH levels increase once a month -Fertilization can occur in both -Gametes are synthesized that each carry one copy of the genome
Gametes are synthesized that each carry one copy of the genome
What does the muscle spindle do?
Gauges muscle length/stretch
Which of the following would increase muscle force? - Increasing activity of acetylcholinesterase - Increasing activity of the sympathetic nervous system - Increasing the action potential threshold in the motor neurons to -30 mV - Increasing the frequency of action potentials in the motor neurons
Increasing the frequency of action potentials in the motor neurons
Beta blockers inhibit beta-adrenergic receptors and are sometimes used by athletes who compete in archery and shooting. Why do you think these athletes in particular use beta blockers?
It decreases the heart rate, and calms them.
What is the golgi tendon?
It measure muscle tension!
Given: Vm = -70 mV, EK = -90 mV, ENa = +60 mV, ECa = +122 mV Remember: ions "want" the cell to be at their equilibrium potential. c) What will happen to the Vm if the cell becomes more permeable to K+? Explain.
K+ goes out
If the second order pain neurons on the right side of the medulla were damaged (i.e. the second neuron in the pathway), which side of the body would lose some pain sensation? - Left side - Both sides - Right side
Left side
If you have a stroke in the right motor cortex that destroys the neurons, what would be the functional consequence? - Right side of body is paralyzed - Left side of body is paralyzed - Patellar reflex is impaired for both legs - No proprioception on the left side of the body
Left side of body is paralyzed
What do mechanoreceptors sense?
Light, touch, pressure, vibration, stretch
What would happen if the concentration of extracellular K+ increased? Assume the intracellular concentration stays the same. What would happen to the membrane potential of a neuron? (Hint: think about how this would change the concentration gradient of K+ and the equilibrium potential for K+. Then figure out the effect on the membrane potential.) - Membrane potential would not be affected -Membrane potential would depolarize -Membrane potential would hyperpolarize
Membrane potential would depolarize
What are the three parts of the brain stem?
Midbrain, pons, medulla oblongata
Cerebellum function?
Motor coordination
What causes skeletal muscle relaxation? - Motor neuron does not fire action potentials - Inhibitory motor neuron releases acetylcholine onto muscle - Descending neurons from brain directly inhibit muscle fibers - Inhibitory interneuron releases GABA onto muscle
Motor neuron does not fire action potentials
Nerve gas inhibits acetylcholinesterase (AChE). It affects the autonomic nervous system, especially the parasympathetic nervous system, because it has two synapses that both use acetylcholine and acetylcholinesterase. What would be a good antidote for nerve gas poisoning, specifically related to the parasympathetic effects? - Nicotinic receptor agonist - Curare (antagonist of nAChR) - Muscarinic receptor antagonist - Beta blocker (beta adrenergic antagonist)
Muscarinic receptor antagonist
Given: Vm = -70 mV, EK = -90 mV, ENa = +60 mV, ECa = +122 mV Remember: ions "want" the cell to be at their equilibrium potential. b) What will happen to the Vm if the cell becomes more permeable to Na+? Explain.
Na+ goes in
What is the rearrangement of the somatosensory called?
Neural plasticity
Which of the following statements about neurotransmitters is correct? Neurotransmitters are enzymes Neurotransmitters binds intracellular receptors and change gene expression Neurotransmitters are lipophobic and stored in vesicles Neurotransmitters leave the neuron via simple diffusion
Neurotransmitters are lipophobic and stored in vesicles
Which of the following statements is correct? - A myofibril is one sarcomere and one sarcoplasmic reticulum - Multiple motor neurons make synapses onto one muscle fiber - Each muscle fiber is made up of one myofibril - One myofibril is made up of many molecules of actin and myosin
One myofibril is made up of many molecules of actin and myosin
What do nociceptors sense?
Painful stimuli (extreme temperatures, extreme pressures, chemicals released by damaged tissue)
Some parts of the brain can be removed if a patient has severe epilepsy. Which of the following parts of the brain should you probably never remove completely because the damage to the patient would be too great (i.e. they would die)? - Pons -Corpus callosum -Right somatosensory cortex -Right cerebellum
Pons
This is a preview for the next lecture about the central nervous system. Please look through this animation (Links to an external site.). Look at both the surface view and inside view and click on the different brain structures to learn their names and what they do. This animation requires Flash. If it does not work for you, then look at chapter 9 in the textbook. Which of the following areas of the brain regulates breathing? - Thalamus -Cerebellum -Pons -Hippocampus
Pons
Which somatosensory receptors send information about skeletal muscles to the brain? - proprioceptors - mechanoreceptors - nociceptors - thermoreceptors
Proprioceptors
Hypothalamus function?
Regulates body temperature
Thalamus function?
Relay station for sensory information
Proprioceptors function?
Sense muscle length and tension
An Arctic Tern (a bird) typically flies 44,000 miles a year during its annual migrations. What kind of muscle fibers likely make up the majority of its wings? - Fast glycolytic - Slow oxidative - Slow glycolytic - Fast oxidative
Slow oxidative
What type of muscle is this? Smooth muscle No answer text provided. Skeletal muscle Cardiac muscle
Smooth Muscle (cells are tightly packed, visible nuclei)
How does the sympathetic nervous system cause blushing? - The sympathetic nervous system causes the release of blood from capillaries - When sweat glands fill with sweat, the skin turns red - The sympathetic nervous system causes skeletal muscles to contract, which makes the skin look red - The sympathetic nervous system increases blood flow throughout the body, which makes the face red
The sympathetic nervous system increases blood flow throughout the body, which makes the face red
[Unrelated to article] What do the autonomic nervous system and somatic motor system have in common in terms of organization? - Their cell bodies are located in the dorsal root ganglia - It takes two neurons to get from the CNS to the target -cell - They both make synapses onto skeletal muscles - Their axons extend from the CNS
Their axons extend from the CNS
Based on the body map in the somatosensory cortex, which of the following areas of the body is most sensitive to touch sensation? - Thumb - Back - Neck - Hip
Thumb
Tetanus toxin is produced by bacteria and when this toxin gets into humans it specifically disables the inhibitory interneurons in the spinal cord. What effects might you see in someone who is infected with this bacteria?
Too much muscle contraction because there is less inhibition of motor neurons
A hemisection is an injury to only one side of the spinal cord. If a patient has damage to the spinal cord only on the right side, how will this affect the following senses: Touch ,Pain, Temperature
Touch: No feeling right side below injury Pain: No pain left side below injury Temperature: No feeling of temperature left side below injury
A toxin from scorpions inhibits the calcium channels in the sarcoplasmic reticulum. What will happen to skeletal muscles that have been exposed to this toxin? - Myosin will not be able to let go of actin - Acetylcholinesterase will no longer function - Tropomyosin will block myosin binding sites on actin - The muscle will not be able to fire action potentials
Tropomyosin will block myosin binding sites on actin
We will learn about the autonomic nervous system (ANS), which controls our organs and smooth muscle. The neurons in the ANS have their cell bodies in the spinal cord and their axon terminals in the peripheral nervous system. Given this information, what structure are these neurons part of? Dorsal root ganglion Dorsal root Ventral root ganglion Ventral root
Ventral Root
Is the corpus callosum white or grey matter? Think about the function of the corpus callosum. -White matter -Grey matter
White matter
Is energy required to set up and maintain the negative membrane potential of neurons? - Yes -No -Only after an action potential
Yes
Will the following postsynaptic responses lead to a hyperpolarization or depolarization or no change to membrane potential? a) Ligand-gated Na+ channel opens b) Ligand-gated cation channel opens (allows Na+, K+ and Ca+2 through) (Clicker question) c) GPCR activation causes more K+ channels to open d) GPCR activates a second messenger system that activates a kinase e) Ligand-gated K+ channel closes f) Ligand-gated Cl- channel opens (Ecl < Vm)
a) Depolarize b) Depolarize c) Hyperpolarization d) NO change e) Depolarization f) Hyperpolarization
3) In the late luteal phase, why do estrogen and progesterone levels fall? a) Rupture of the dominant follicle b) Degeneration of the corpus luteum c) An inhibitory effect of LH on secretory activity of the corpus luteum d) Endometrial lining is shed e) All of the above
b) Degeneration of the corpus luteum
1) Why do LH levels rise at the end of the follicular phase? a) Progesterone inhibition is removed b) GnRH signals to the granulosa cells to release more LH c) Estrogen stimulates LH release from the anterior pituitary d) Less LH is degraded in the blood e) The growing follicle releases more LH
c) Estrogen stimulates LH release from the anterior pituitary Positive feedback occurs
3) If a neuron has equal permeability to sodium and potassium ions, would the resting membrane potential of that cell be more negative or less negative than -70 mV? In other words, will the Vm depolarize or hyperpolarize?
depolarize!
The image below shows a reflex for micturition, otherwise known as urination. The reflex shown below is what happens in babies, who do not control urination. The sensory neuron responds when the bladder stretches (i.e. filled with urine). The external sphincter is made of skeletal muscle and when it is contracted, urine cannot leave the bladder. When the external sphincter is relaxed, urination occurs. Note that two neurons are labeled A and B: neuron A is the red neuron in the spinal cord that makes a synapse on neuron B, and neuron B is making a synapse onto the external sphincter. Think about the logic of this circuit to figure out what type of neurons A and B are. Ignore the middle blue neurons; they are not important to answer this question. Neuron A is a/an ________ and neuron B is a/an __________ .
inhibitory interneuron , motor neuron
