Biology Lession 3

Where are the neuron cell bodies located in the sympathetic nervous system?

far from the effectors

What is the full name of the hormone hCG What does it do?

human Chorionic Gonadotropin

Why does it take a stronger stimulus than normal to cause an action potential during the relative refractory period?

hyperpolarization of the membrane, that is, the membrane potential becomes transiently more negative than the normal resting potential. Until the potassium conductance returns to the resting value, a greater stimulus will be required to reach the initiation threshold for a second depolarization. The return to the equilibrium resting potential marks the end of the relative refractory period

What makes up the nervous system?

includes the brain, spinal cord, peripheral nerves, neural support cells AND sensory organs such as the eyes and ears

Brownian motion

the presumably random drifting of particles suspended in a fluid (a liquid or a gas) or the mathematical model used to describe such random movements, which is often called a particle theory.

Where are the neuron cell bodies located in the parasympathetic nervous system?

very close to, or inside, the effector

About what voltage is th3e threshold potential at?

-55mV

The opening of the voltage-gated sodium channels causes a sudden spike in the membrane potential, from _____ mV to somewhere around ____mV What is this process referred to as?

-70 mV to around +40mV Depolarization

... Draw a cross-section of the cochlea showing the three compartments and the organ of Corti.

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... Draw a diagram of the human eye and label the following: Cornea, sclera, pupil, iris, aqueous humor, vitreous humor, lens, suspensory ligaments, ciliary muscles, retina, and optic nerve.

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... Draw a nephron, label the parts, and describe the function of each

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... Draw and label all of the parts of the inner ear.

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... How do you correct far- and near-sightedness?

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... What is the Renal Pelvis and Ureter?

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What percentage of all neurons are interneurons?

90%

Polycystic Ovary Syndrome results in numerous follicles, or fluid-filled egg sacs, forming on the surface of a woman's ovaries. Ovulation is greatly inhibited or irregular and multiple cysts build up over time. A researcher has discovered that female lab animals who are given high levels of "male hormones," called androgens, exhibit almost identical symptoms. The researcher hopes to develop a drug that associates with the androgens in a woman's body and prevents them from binding to their receptors. To be effective, it is important that the drug: A. be lipid-soluble B. be water-soluble C. have a short half-life under physiological conditions D. bind reversibly to its target

A

Which of the following most completely describes the nerve endings in the eye that cause pupil dilation? A. Sympathetic, norepinephrine B. Parasympathetic, acetylcholine C. Sympathetic, acetylcholine D. Parasympathetic, norepinephrine

A

What type of neurotransmitter is found at the ganglia and effectors of the sympathetic nervous system?

Acetocholine at the ganglia and norepinephrine at the effector

What is the neurotransmitter used in the parasympathetic nervous system?

Acetylcholiine

"Absolute refractory period" vs "relative refractory period"

After initiation of an action potential, the refractory period is defined two ways: (1) The absolute refractory period is the interval during which a second action potential absolutely cannot be initiated, no matter how large a stimulus is applied. (2)The relative refractory period is the interval immediately following during which initiation of a second action potential is inhibited but not impossible The relative refractory period immediately follows the absolute

What is another term for an activator? Inhibitor?

Agonist = activator Antagonist = inhibitor

Which or the following statements is/are true concerning the use of neurotransmitters in the autonomic nervous system? I. All parasympathetic synapses utilize acetylchholine II. All sympathetic synapses utilize acetylcholine III. Both acetylcholine and norepinephrine are used by the parasympathetic nervous system IV. Acetylcholine is used at pre-ganglionic synapses in the sympathetic nervous system A. I and III B. I and IV C. II and III C. II and IV

B

Patients with a new disease suffer from two main problems: 1) dangerously high blood pressure and 2) erratic, abnormally high calcium blood concentration. Blood samples from affected patients show a very high concentration from an unknown protein. This protein is assayed and found to be a recognized human hormone. Based on the information in the passage, which of the following is most likely the identity of this hormone? A. Calcitonin B. PTH C. Aldosterone D. ADH

B ; Aldosterone and ADH would both account for only one symptom, Calcitonin (as mentioned above) would not account for any of them, and PTH could account for both (by its normal effect of increasing blood calcium and via an increase in blood pressure via increased osmolarity). Although it may be tempting to pick C or D, it is impossible to say that one is more likely than the other and B is the better answer because it accounts for both symptoms.

As winter approaches, the Siberian muskrat gorges itself on high-carbohydrate food in order to store up fat for its long hibernation. Which of the following hormones is likely to be found in highest concentration in the muskrat's liver during the fall and winter, receptively? A. glucagon, then insulin B. insulin, then glucagon and cortisol C. insulin, then glucagon D. glucagon, then insulin and cortisol

B ; Recall that insulin and glucagon, like all hormones, tend to return things to normal physiological levels. Thus, while the muskrat is gorging on carbs, the blood concentration of glucose due to the absorption of these carbs will be higher than normal and insulin would be secreted to return things to normal. During the winter, there will be NO absorption because the muskrat won't be eating, so blood glucose will be lower than normal and glucagon will be present to raise the blood glucose levels to normal. Next, you must ask yourself what cortisol does? It is a stress hormone whose main effect is to promote gluconeogenesis (the reverse of glycolysis) and promote fat metabolism. This is very likely to be present during a stressful hibernation when the muskrat will need to accomplish both of these tasks in order to maintain its normal blood glucose levels. B is thus the best answer.

Which of the following statment is/are true concerning the organ of corti? I. Small microtuble-filled membrane extensions, called "hair cells" sense disturbances in the fluid and transmit these movements into neural signals II. It is located inside the cochlea III. it contains the Semi-Circular Canals, which help maintain balance and orientation A. I only B. II only C. II and III D. I and II

B; The Organ of Corti is the structure inside the cochlea that transfers fluid motions into a nerve signal. It does not contain microtubules (and doesn't contain cilia!), so Statement I is false. Statement II is true. Statement III is false because the semi-circular canals are not located within the Organ of Corti.

All of the following provide an accurate description of a human hormone and one of its major effects, EXCEPT: A. FSH stimulates the development of sperm in males B. Estrogen stimulates a dramatic increase in leutinizing hormone C. Prolactin stimulates the secretion of milk from the mammory glands D. Calcitonin inhibits the proliferation of osteoclasts

C ; Hopefully you're getting the point by now . . . that you really DO need to know that hormone chart inside and out. A will be marked wrong by many students because they think of the female reproductive system when they see FSH. In fact, it regulates both sexes similarly, stimulating the testes to develop and nurture gametes. Estrogen does cause an increase in LH during menstruation, known as the "luteal surge." Answer D is also true, calcitonin does inhibit osteoclasts. C, however, is false because prolactin stimulates milk production (lactation) not milk excretion (or "let down").

The hormone TSH most likely has its affect via which of the following mechanisms? A. TSH dissolves through the nuclear membrane of thyroid cells into the cytoplasm, where it increases translation B. TSH binds to a receptor on the cell membrane, where it initiates a cascade that increases the metabolic activity of thyroid cells. C. TSH bind to a receptor on the cell membrane, where it initiates a cascade that increases transciption. D. TSH dissolves through the nuclear membrane where it increases DNA replication

C ; TSH is a peptide hormone, so it CANNOT dissolve thru the membrane, eliminating answer choices A and D. B is false because an increase in metabolic activity would not have the effect which TSH has. TSH stimulates the thyroid to secrete T3 and T4, which in turn increases basal metabolic rate. To make this happen, TSH must in some way increase the transcription of DNA into the mRNA molecules that are then translated into T3 and T4 at the rough ER and exported from the cell; answer choice C describes this very action and is thus the best answer.

All of the following changes to the physiology of the cell membrane of a neuron would decrease the sensitivity of that neuron to the propagation of a new action potential, EXCEPT: A. a complete inhibition of ATP production and availability in the cell B. administration of a drug that up-regulates the function of the sodium-potassium pump C. increased selective permeability of the neuronal membrane to sodium ions D. increased rate of diffusion of potassium ions relative to sodium ions

C; See manual for explication

Patient B suffers from calcinuria, a disease resulting in chronically low blood calcium. Which hormone will be found in highest concentration in his blood.

Calcitonin

What do the ciliary muscles do when you focus on a book very near your face? What happens to the curvature of the lens? Focal point? power of the lens?

Ciliary muscles contract, lens becomes more curved (convex), focal point decreases and power increases.

Compare and Contrast: Exocrine and Endocrine Glands

Exocrine glands release enzymes or other liquids into the external environment (which includes the digestive tract and epithelial lined orifices; substances released include sweat, oil, mucus, digestive enzymes, etc.) Endocrine glands release hormones into the internal fluids of the body (e.g. blood, lymph, etc)

What hormones are Steroids?

Cortisol and Aldosterone from the Adrenal Cortex and Estrogen, progesterone and Testosterone from the gonads

Which of the following best accounts for the fact that a stronger stimulus is required to initiate an action potential during the relative refractory period? A. Compared with resting potential, sodium ion concentration inside the cell is much higher, requiring a larger threshold stimulus B. Compared with resting potential, sodium ion concentration inside the cell is much lower, requiring a larger threshold stimulus. C. Excess potassium ions inside the cell create a larger negative potential, which must be overome be a larger threshold stimulus. D. Excess potassium ions outside the cell create a larger negative potential, which must be overcome by a larger threshold stimulus

D

Which of the following statements best describes the mechanism of function of the inner ear? A. The tympanic membrane, displaced by collisions with air molecules, displaces the malleus, then the incus, then the stapes, resulting in an increase in displacement at the oval window. B. The ympanic membrane, displaced by collisions with air molecules, displaces the incus, then the malleus, then the stapes, resulting in an increase in pressure at the oval window C. The tympanic membrane, displaced by sound waves, displaces the incus, the malleus, then the stapes, resulting in a decrease in pressure at the oval window. D. The tympanic membrane, displaced by sound waves, displaces the malleus, then the incus, then the stapes, resulting in a decrease in displacement at the oval window

D ; First, note that both the term "displaced by collisions with air molecules" and the term "displaced by sound waves" are correct. The key here is to first find the choice with the correct order of bones: maleus, incus, then stapes. This narrows it to A or D. A is wrong and D is correct because the displacement at the oval window compared to the eardrum is DECREASED. This difference in input/output displacement creates the lever action of the ear and magnifies the pressure at the oval window.

Why is visceral pain often referred (i.e., felt at a location other than the actual source)?

It is part of the sensory subdivision of the autonomic nervous system which is not well developed.

Patient B has low blood glucose levels. Which hormone is likely to be in highest concentration in his blood?

Glucagon

What hormones come from the Pancreas?

Gucagon and Insulin (also releases several digestive enzymes, but this is an exocrine function: not an endocrine function)

What does the Middle Ear include?

Includes the tympanic membrane and three middle ear bones: Malleus, incus & stapes

Patient A has high blood glucose levels. Which hormone is likely to be found in highest concentration in her blood?

Insulin

What hormones are tyrosines?

T₃/T₄ which are lipid-soluble Epi/Norepi which are water-soluble

When do the K⁺ channels open in action potential propagation?

Just before maximum depolarization is reached, the Na⁺ channels begin to close and the K⁺ channels begin to open

What does most of the bending of light rays?

Light rays are bent most by the cornea, and subsequently adjusted by the lens

What are the functions of the Kidney

Maintain homeostasis of bodily fluids (especially blood plasma) Control plasma pH regulate blood volume and pressure

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Neurons are: (1)Frozen in G₀ phase (unable to divide) (2) Depend entirely on glucose for energy (3) Don't require insulin for glucose uptake (4) Have very low glycogen and Oxygen storage capability and thus require high perfusion (blood flow)

Patient A has osteoporosis. Which hormone will be found in highest concentration in her blood?

Parathyroid

Rods vs Cones

Rods = highly sensitive, perceive black and white only Cones = less sensitive, perceive color

What two pain divisions make up the motor subdivision of the autonomic nervous system?

Sympathetic and Parasympathetic

What does the outer ear include?

The Pinna (earlobe) and auditory canal

What organ secretes two types of hormones?

The Thyroid. It secretes both a tyrosine derivative and a peptide hormone

How low does the membrane potential go during hyperolarization and why?

The potassium channels are somewhat slow to close as the membrane potential approaches -70 mV. Thus, the membrane potential actually dips to around -90mV before gradually returning to the resting potential.

Describe the interplay between: The juxtaglomerular apparatus, the renin-angiotensin pathway, aldosterone, and the distal convoluted tubules of the kidney

The renin-angiotensin system (RAS) or the renin-angiotensin-aldosterone system (RAAS) is a hormone system that regulates blood pressure and water (fluid) balance. When blood volume is low, juxtaglomerular cells in the kidneys secrete renin directly into circulation. Plasma renin then carries out the conversion of angiotensinogen released by the liver to angiotensin I. Angiotensin I is subsequently converted to angiotensin II by the enzyme angiotensin converting enzyme found in the lungs. Angiotensin II is a potent vaso-active peptide that causes blood vessels to constrict, resulting in increased blood pressure. Angiotensin II also stimulates the secretion of the hormone aldosterone from the adrenal cortex. Aldosterone causes the distal convoluted tubules of the kidneys to increase the reabsorption of sodium and water into the blood. This increases the volume of fluid in the body, which also increases blood pressure. If the renin-angiotensin-aldosterone system is too active, blood pressure will be too high. There are many drugs that interrupt different steps in this system to lower blood pressure

Where are Electrical Synapses found in humans?

The retina, smooth muscle, cardiac muscle, and the CNS

Compare and contrast ureters and urethra

The ureters carry urine from the renal pelvis portion of the kidneys to the bladder. The urethra carries urine from the bladder to the external urinary orifice. You have two ureters, but only one urethra.

What is the slowest part of signal transmission down a nerve?

Transmission across the synapse is by far the slowest part of signal transmission

juxtaglomerular apparatus

a specialized region of the nephron responsible for production and secretion of the enzyme renin

What does ADH do?

acts on the kidney's collecting duct making it permeable to water. In the absence of ADH the collecting duct is impermeable to water. Because the collecting duct passes through the highly-concentrated medulla, as soon as the membrane become permeable there is a large net flow of water out of the filtrate, concentrating the urine. The net effect = water retention and increased blood pressure

What are ependymal cells

cells lining the cerebrospinal fluid cavities

What does the Inner ear include

the Cochlea, semicircular canals and the vestibulocochlear nerve