BIOL 1119 Lecture 10: Lecture 10 notes Cardiac Output

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plumfrog200

19 Aug 2016

School

Northeastern University

Department

Biology

Course

BIOL 1119

Professor

Christopher Richardson

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Document Summary

Sr = means more calcium enters from outside cell and more calcium from inside sr per unit time. !1: this means that the cardiocyte can actually reach the positive membrane. Also promotes to set the next contraction more quickly meaning this increases heart rate as well. Affect sa and av nodes (do not innervate ventricular myocardium/ only affect speed of contraction) Secretes acetylcholine (ach) which binds to muscarinic receptors on nodal cells: opens k+ channels: use g protein to open up the ion channel (metabotropic) Nodal cells hyperpolarized as k+ exit (nodal do not get back to threshold as often) Normally, potassium gates do not open until depolarization. Early exit of potassium counteracts the slow entry of sodium (which normally without potassium exit, makes the cell more positive) Vagus nerves act faster on heart than sympathetic nerves. Ach acts via the g protein to open up ion channels in plasma membrane of nodal cell.

Related Questions

QUESTION 1

Which of the following is an example of an extracellular signal molecule?

	a.	IP₃
	b.	cAMP
	c.	Insulin
	d.	Diacylglycerol

2 points

QUESTION 2

Nuclear hormone receptors _____

	a.	Bind to water soluble ligands
	b.	Activate second messengers
	c.	Regulate transcription in response to ligand binding
	d.	Are normally located on the plasma membrane

2 points

QUESTION 3

Which of the following does not occur when a receptor tyrosine kinase is bound by ligand?

	a.	Phosphorylation of the RTK
	b.	Cytoplasmic proteins bind the phosphorylated RTK
	c.	Dimerization of the RTK
	d.	The RTK binds to DNA to regulate transcription

2 points

QUESTION 4

Which of these is a logical signal-transduction pathway?

	a.	An intracellular receptor activates phospholipase C, which cleaves a membrane protein to form IP₃, which then activates the opening of an ER channel protein, which releases cyclic AMP into the cytoplasm, where it binds to an intracellular enzyme that carries out a response.
	b.	A G-protein-linked receptor activates G protein, which activates phospholipase C, which cleaves a membrane lipid to form IP₃, which binds to a calcium channel on the ER, which opens to release calcium ions into the cytoplasm, which bind to an intracellular enzyme that carries out a response.
	c.	An ion-channel receptor opens, allowing a steroid hormone to enter the cell; the steroid hormone then activates protein kinases that convert GTP to GDP, which binds to an intracellular enzyme that carries out a response.
	d.	A tyrosine-kinase receptor activates adenylyl cyclase, which activates phospholipase C, which converts ATP into cyclic AMP, which binds to an intracellular enzyme that carries out a response.

2 points

QUESTION 5

Which of the following is an example of signal amplification?

	a.	activation of an enzyme molecule
	b.	activation of a specific gene by a growth factor
	c.	Breakdown of many cAMP molecules
	d.	activation of 100 molecules by a single signal binding event

2 points

QUESTION 6

Consider a signal transduction pathway that utilizes cAMP as a second messenger to activate PKA (Protein Kinase A). Which of the following situations will result in the cellular response?

		The G protein releases GDP and binds to GTP
		The target protein (adenylyl cyclase) is inactive
		The regulatory subunits of PKA (Protein Kinase A) are bound to the catalytic subunits
		The appropriate G protein is bound to GDP

2 points

QUESTION 7

Which of the following is found in only some signal transduction pathways? [In other words, which is not found in all signal transduction pathways?]

		Receptor protein
		Extracellular signal molecule
		Intracellular signaling molecule
		Cellular response
		Effector protein

2 points

QUESTION 8

The enzyme that specifically catalyzes the conversion of ATP to cAMP is:

		Adenylyl phosphatase
		Adenylyl kinase
		Adenylyl dehydrogenase
		Adenylyl cyclase

2 points

QUESTION 9

If an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?

		It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane.
		It would employ a transduction pathway directly from an external messenger.
		It would be able to carry out reception and transduction but would not be able to respond to a signal.

2 points

QUESTION 10

A hormone signal is sent from the brain to other parts of the body via the bloodstream. Why do only certain cells respond to this signal?

		Hormones do not last long enough in the bloodstream to stimulate a cellular response
		Only cells that have a specific transcription factor gene will be able to respond to the signal
		Only cells in the immediate vicinity of the cell sending the signal will respond
		Only cells that have a receptor for the specific signal will be able to respond to it

cerisehedgehog846

a) Which of the following statements about the autonomic nervous system is INCORRECT?

A The preganglionic fibres in the parasympathetic division are usually long compared to the postganglionic fibres

B The sympathetic division mediates responses that allow the body to respond to âflight and frightâ situations

C The ganglia of the sympathetic division are usually close to the spinal cord

b) Glutamate is an example of an excitatory amino acid neurotransmitter that acts via direct synaptic transmission when it is released from presynaptic neurons in the brain

Based on the background information, which of the following is a CORRECT statement regarding events at the synaptic cleft after glutamate is released?

A Glutamate acts by stimulation of receptors on the presynaptic neuron

B The postsynaptic glutamate receptors are in the family of tyrosine-kinase linked receptors

C On the postsynaptic membrane, glutamate activates ligand-gated sodium channels, which are an example of ion-channel linked receptors

D The events at this synapse are an example of electrical transmission

E The pathway of receptor activation includes activation of a signal transduction pathway and production of second messengers

D The adrenal medulla is a sympathetic ganglion

E The parasympathetic nerves arise from the brain stem and the sacral region of the spinal cord

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BIOL 1119 Lecture 10: Lecture 10 notes Cardiac Output

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