Autonomic Nervous System Overview

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Questions and Answers

Which receptors are specifically activated by acetylcholine?

alpha-1 and alpha-2 adrenergic receptors

muscarinic receptors (correct)

nicotinic receptors (correct)

beta-1 adrenergic receptors

Which hormone is least likely to be involved in carbohydrate metabolism regulation?

intermedin (correct)

glucagon

insulin

adrenaline

What causes a decrease in body temperature?

decreased secretion of thyroid-stimulating hormone

inhibition of sympathetic centers in the hypothalamus

stimulation of heat receptors in the skin (correct)

chemical thermoregulation inhibited (correct)

Which statement about hypothalamic thermoregulation centers is true?

They include heat dissipation centers Signup and view all the answers

What effect does ADH have on the kidneys?

increases water permeability of collecting ducts Signup and view all the answers

Which of the following is NOT caused by vasopressin?

increased diuresis Signup and view all the answers

Which symptom is NOT typical of Basedow's disease?

decreased body weight Signup and view all the answers

How are mechanoreceptors primarily excited?

mechanical deformation of the receptor Signup and view all the answers

What is the main effect of active vitamin D3 on calcium levels in the plasma?

Increases the concentration of Ca2+ in plasma Signup and view all the answers

After abundant carbohydrate intake, which of the following metabolic processes is NOT expected to occur?

Increased glycogenolysis Signup and view all the answers

What neurotransmitter is secreted by neuron number 2 in the sympathetic nervous system pathway?

Noradrenaline Signup and view all the answers

Which of the following statements about salivation is correct?

Salivation decreases during pregnancy Signup and view all the answers

What physiological change is commonly associated with the stimulation of the parasympathetic nervous system?

Bronchoconstriction mediated by M-cholinergic receptors Signup and view all the answers

Which of the following accurately describes Somatomedin C?

Has insulin-like effects Signup and view all the answers

On the 14th day of a normal menstrual cycle, what occurs regarding the endometrium?

The concentration of circulating progesterone is at its peak Signup and view all the answers

What hormonal changes are expected in plasma after a large dose of insulin is administered intravenously?

Decreased growth hormone and glucagon Signup and view all the answers

Which of the following substances is considered a sympathomimetic?

Adrenaline Signup and view all the answers

Which channels are involved in chemical-dependent ion transmission on the postsynaptic membrane?

Channels for calcium Signup and view all the answers

What type of fibers do the axons of preganglionic neurons belong to?

Type B fibers Signup and view all the answers

Which of the following processes does NOT occur when the sympathetic nervous system is stimulated?

Insulin secretion Signup and view all the answers

What effect does stimulation of the sympathetic nervous system have on the radial muscle fibers of the iris?

Contraction and pupil dilation (mydriasis) Signup and view all the answers

Which of the following is NOT a sympathetic reaction that occurs during physical or mental stress?

Decreased glycolysis in the liver and muscles Signup and view all the answers

Where are nicotinic receptors primarily located?

At the level of autonomic sympathetic ganglia Signup and view all the answers

Which statement about synaptic transmission in sympathetic ganglia is true?

It involves acetylcholine release Signup and view all the answers

Which hormone is primarily responsible for stimulating gluconeogenesis?

Glucagon Signup and view all the answers

Which change does NOT occur in type 1 diabetes?

Increased blood pH Signup and view all the answers

What is the effect of cortisol during protein metabolism?

Increased protein breakdown Signup and view all the answers

Primary hyperthyroidism is characterized by which of the following hormonal levels?

T4 and T3 are elevated and TSH is decreased Signup and view all the answers

Beta-receptors activate G-proteins, which subsequently activate which enzyme?

Adenylate cyclase Signup and view all the answers

How does stimulation of the sympathetic nervous system affect the pupil diameter?

Increases pupil diameter Signup and view all the answers

What effect do sympathetic nerves have on the heart rate and force of contractions?

Cause positive inotropic and chronotropic effects Signup and view all the answers

How does intense stimulation of the vagus nerve affect the heart?

Decreases the strength and frequency of contractions Signup and view all the answers

Which statements about gluconeogenesis are correct?

Gluconeogenesis can occur during fasting. Signup and view all the answers

Which substances can effectively constrict the pupil?

Acetylcholine Signup and view all the answers

Which of the following factors can increase insulin secretion?

Leptin Signup and view all the answers

What statements about parathyroid hormone (PTH) are accurate?

PTH is involved in calcium homeostasis. Signup and view all the answers

Which statements regarding cortisol are true?

Cortisol has anti-inflammatory effects. Signup and view all the answers

Identify the correct factors that increase calcium absorption.

Vitamin D3 presence Signup and view all the answers

Which nervous system stimulation is responsible for bladder muscle contraction?

Acetylcholine Signup and view all the answers

Which of the following statements about ADH is true?

ADH deficiency leads to increased diuresis. Signup and view all the answers

Study Notes

Autonomic Nervous System: Neurotransmitters & Receptors

Acetylcholine is a parasympathomimetic neurotransmitter, meaning it mimics the effects of the parasympathetic nervous system.
Atropine is a parasympatholytic drug, blocking the actions of acetylcholine at muscarinic receptors.
Aminazaine is not a parasympathomimetic.

Sympathetic Nervous System

Adrenaline and noradrenaline are sympathomimetic neurotransmitters, stimulating the sympathetic nervous system.
Sympathetic stimulation leads to pupil dilation, increased heart rate, and blood pressure, as well as bronchodilation.
Insulin secretion is inhibited by sympathetic stimulation.

Neuronal Axon Types

Preganglionic neurons of the autonomic nervous system have myelinated axons classified as type A fibers.
Postganglionic neurons have unmyelinated axons classified as type C fibers.

Ion Channels & Synapse Transmission

Chemically-dependent ion channels are responsible for the transmission of nerve impulses across synapses. These include sodium, calcium, potassium, and chloride channels.
Sympathetic ganglia use nicotinic receptors for neurotransmission, with acetylcholine as the primary neurotransmitter.
Acetylcholine binds to muscarinic receptors in parasympathetic effector organs.

Hormonal Regulation of Metabolism

Insulin, glucagon, and thyroxine are involved in the regulation of carbohydrate metabolism, while intermedin plays a role in skin pigmentation.
Hypothalamic thermoregulation centers control body temperature via heat production and dissipation mechanisms.
Cortisol, thyroid hormones, and growth hormone are involved in fat metabolism, while parathyroid glands play a role in calcium and phosphate balance.
Parathyroid hormone increases blood calcium levels by stimulating osteoclasts and decreasing calcium excretion by the kidneys.
Vitamin D3 also increases calcium absorption in the intestines.

Effects of Hormonal Imbalances

Basedow's disease (hyperthyroidism) is characterized by increased heart rate, thermogenesis, appetite, and oxygen consumption. The patient may show weight loss despite increased appetite.

Neurotransmitter Effects

Norepinephrine and epinephrine can constrict the pupil by stimulating the radial muscles of the iris.
Acetylcholine acts on the circular muscles of the iris, causing pupil constriction (miosis).
Atropine, by blocking muscarinic receptors, would dilate the pupil.

Insulin & Glucose Metabolism

Insulin is secreted in response to increased blood glucose levels, promoting glucose uptake and utilization by cells.
Insulin secretion can be stimulated by various factors including beta-adrenergic stimulation and leptin.
Gluconeogenesis, the production of glucose from non-carbohydrate sources, occurs in the liver and is stimulated by glucagon and cortisol.
Glycogenesis, the synthesis of glycogen, is activated when cellular ATP levels are high, typically after carbohydrate intake.
Glycogenolysis, the breakdown of glycogen, is stimulated by glucagon and epinephrine.

Impacts of Hormonal Disorders

Diabetes mellitus type 1 is characterized by insulin deficiency, leading to hyperglycemia, osmotic diuresis, increased lipolysis, and ketone body formation.
Cortisol increases protein breakdown, while insulin promotes protein synthesis.

Effects of Sympathetic & Parasympathetic Stimulation

Sympathetic stimulation increases heart rate and force of contraction (positive inotropic and chronotropic effects) while parasympathetic stimulation has the opposite effect (decreases heart rate).
Sympathetic stimulation also increases oxygen consumption by the body.
Parasympathetic stimulation promotes energy storage and conservation.

Effects of Other Hormones

Somatomedin C, also known as IGF-1, has insulin-like effects and is stimulated by growth hormone (GH).
Oxytocin, released from the posterior pituitary, stimulates uterine contractions during labor and milk ejection during breastfeeding.
ADH (vasopressin), also from the posterior pituitary, increases water reabsorption in the kidneys, leading to concentrated urine and decreased diuresis.

Summary of Important Hormones & Their Effects

Insulin: lowers blood glucose, promotes glucose uptake and utilization, stimulates protein synthesis, inhibits lipolysis
Glucagon: raises blood glucose, stimulates glycogenolysis, promotes gluconeogenesis
Cortisol: increases blood glucose, stimulates gluconeogenesis, inhibits glucose uptake by cells, increases protein breakdown, influences immune function
Growth hormone (GH): stimulates protein synthesis, promotes growth, increases lipolysis, decreases glucose uptake
Thyroid hormones (T3 & T4): regulate metabolism, increase oxygen consumption, increase heart rate, promote growth and development
Parathyroid hormone (PTH): increases blood calcium levels, stimulates osteoclast activity, decreases calcium excretion by the kidneys
Vitamin D3: increases calcium absorption in the intestines, regulates bone metabolism
Aldosterone: regulates electrolyte balance, increases sodium reabsorption in the kidneys
ADH (vasopressin): increases water reabsorption in the kidneys, regulates blood pressure
Oxytocin: stimulates uterine contractions and milk ejection

These study notes highlight key concepts related to the autonomic nervous system, neurotransmitters, receptors, and hormonal regulation of physiological processes. You should now have a good foundation for deeper study in this area!

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Description

This quiz explores the key components of the autonomic nervous system, focusing on neurotransmitters like acetylcholine and their receptors. It also examines the sympathetic and parasympathetic systems, as well as the types of neuronal axons involved. Test your knowledge on these fundamental concepts of neurobiology!