EXAM 1 Chapters 16 & 17 Flashcards

What is the Autonomic Nervous System (ANS)?

A division of the peripheral nervous system that maintains homeostasis and controls involuntary functions

What are examples of functions controlled by the ANS?

Heartbeat, digestion, and pupil dilation/constrictionare examples of functions controlled by the ANS.

What is the Somatic Nervous System (SNS)?

A division of the peripheral nervous system responsible for voluntary movements

What is a receptor?

Detects a stimulus

What is an effector?

Produces a response to the stimulus

What is the main difference between the SNS and ANS?

SNS = mostly voluntary. ANS = involuntary/automatic

What are the effectors of the SNS?

Skeletal muscles

What are the effectors of the ANS?

Glands, smooth muscle, and cardiac muscle

What is an example of a receptor and effector in the SNS?

Skin receptors detect heat, and skeletal muscles contract to pull away

What is the parasympathetic division?

Rest and digest — helps the body rest and recover

What is the sympathetic division?

Fight or flight — prepares the body for danger

What is a preganglionic fiber?

An axon that carries a message from the central neuron to the ganglion

What is a postganglionic fiber?

Carries the message from the ganglion to an organ

Where do sympathetic preganglionic neurons originate?

In the lateral horn of the thoracic and first two lumbar spinal segments

Where do sympathetic postganglionic neurons originate?

At the ganglion, then carry the message to the organ

Where do parasympathetic preganglionic neurons originate?

In the cranial nerve nuclei and sacral segments of the spinal cord

Where do parasympathetic postganglionic neurons originate?

In terminal ganglia located in or very close to the target organs

Are ANS ganglia inside or outside the central nervous system?

Outside the central nervous system

What neurotransmitter do sympathetic preganglionic neurons release, and what receptor do they target?

Acetylcholine (ACh) → Nicotinic receptors

What neurotransmitter do parasympathetic preganglionic neurons release, and what receptor do they target?

Acetylcholine (ACh) → Nicotinic receptors

What neurotransmitter do sympathetic postganglionic neurons release, and what receptors do they target?

Norepinephrine (NE) → Adrenergic receptors

What neurotransmitter do parasympathetic postganglionic neurons release, and what receptors do they target?

Acetylcholine (ACh) → Muscarinic receptors

What are several things activated by the sympathetic nervous system?

Pupil dilation, decreased digestion, sweating, increased blood pressure, increased heart rate, increased breathing rate, and decreased saliva

What are several things activated by the parasympathetic nervous system?

Increased digestion, decreased heart rate, pupil constriction, increased saliva, bowel movements, increased urination, and airway constriction

What activates nicotinic receptors?

Acetylcholine (ACh)

What activates muscarinic receptors?

Acetylcholine (ACh)

What activates adrenergic receptors?

Norepinephrine (NE)

What is an agonist?

A substance that turns on a receptor and causes a response

What is an antagonist?

A substance that blocks a receptor and prevents a response

What is the 1st part of a reflex arc?

Sensory receptor

What is the 2nd part of a reflex arc?

Sensory (afferent) neuron

What is the 3rd part of a reflex arc?

Integrating center

What is the 4th part of a reflex arc?

Motor (efferent) neuron

What is the 5th part of a reflex arc?

Effector

What is the order of a reflex arc?

Receptor → Sensory → Integrating center → Motor → Effector

What are the glands of the endocrine system?

Pituitary, thyroid, parathyroid, adrenal, and pineal glands

What is the main difference between endocrine and exocrine glands?

Endocrine glands are ductless; exocrine glands use ducts

How do endocrine glands release hormones?

Directly into the bloodstream

How do exocrine glands release their secretions?

Through a duct

How does the endocrine system send signals?

Hormones travel through the bloodstream to target organs and tissues

What does the endocrine system use to control the body?

Hormones

What does the nervous system use to control the body?

Electrical signals

What is the main difference between the endocrine and nervous systems?

Endocrine = hormones Nervous = electrical signals

What are hormones?

Chemical messengers that travel through the bloodstream

What are circulating hormones?

Hormones that travel through the bloodstream to work somewhere else

What are local hormones?

Hormones that work where they are or close by

Where do water-soluble hormones bind?

To receptors outside the cell

What are examples of water-soluble hormones?

Epinephrine, norepinephrine, and dopamine

Where do lipid-soluble hormones bind?

To receptors inside the cell

What are examples of lipid-soluble hormones?

Cortisol and thyroid hormones

What controls hormone release?

Negative feedback

What are some responses to hormones?

Protein synthesis, changes in cell growth, and stimulation of secretion

What is a positive feedback loop?

When a change increases until the process is complete

What is an example of a positive feedback loop?

Childbirth — oxytocin causes contractions, which triggers more oxytocin to be released

What is a negative feedback loop?

When a change decreases or stops to bring the body back to homeostasis

What is an example of a negative feedback loop?

When cortisol levels get too high, the body decreases cortisol production

What two brain structures release hormones that control other endocrine structures?

Hypothalamus and pituitary gland

What structure is affected by the releasing hormones of the hypothalamus?

The anterior pituitary gland

What hormones are released from the hypothalamus?

Releasing and inhibiting hormones

What is GHRH and what does it do?

Growth hormone-releasing hormone → anterior pituitary → stimulates GH release

What is TRH and what does it do?

Thyrotropin-releasing hormone → anterior pituitary → stimulates TSH release.

What is CRH and what does it do?

Corticotropin-releasing hormone → anterior pituitary → stimulates ACTH release

What is PRH and what does it do?

Prolactin-releasing hormone → anterior pituitary → stimulates prolactin release

What is GnRH and what does it do?

Gonadotropin-releasing hormone → anterior pituitary → stimulates FSH & LH release

What is GHIH and what does it do?

Growth hormone-inhibiting hormone → anterior pituitary → inhibits GH release

What is PIH and what does it do?

Prolactin-inhibiting hormone → anterior pituitary → inhibits prolactin release

What hormones are released from the anterior pituitary?

GH, TSH, ACTH, FSH, LH, PRL, and MSH

What is hGH and what does it do?

Human growth hormone → body tissues → promotes body growth

What is TSH and what does it do?

Thyroid-stimulating hormone → thyroid gland → stimulates T3 & T4 release

What is FSH and what does it do?

Follicle-stimulating hormone → ovaries/testes → stimulates production and maturation of ova & sperm

What is LH and what does it do?

Luteinizing hormone → ovaries/testes →
Females: ovulation + estrogen/progesterone production
Males: testosterone production

What is PRL and what does it do?

Prolactin → mammary glands → stimulates breast milk production

What is ACTH and what does it do?

Adrenocorticotropic hormone → adrenal cortex → stimulates release of glucocorticoids, such as cortisol

What hormones are released from the posterior pituitary?

Oxytocin and vasopressin (ADH)

What is OT and what does it do?

Oxytocin → uterus & mammary glands → causes childbirth contractions and milk release

What does ADH stand for?

Antidiuretic hormone

What is another name for ADH?

Vasopressin

What does ADH do?

Kidneys → increases water absorption

How does the hypophyseal portal system work?

Carries hypothalamus hormones directly to the anterior pituitary

What is the purpose of the hypophyseal portal system?

To deliver hypothalamus hormones to the anterior pituitary

Where is the thyroid gland located?

In the neck around the trachea, below the larynx

What hormones does the thyroid release?

T3, T4, and calcitonin

What do T3 and T4 control?

Metabolism, body temperature, growth, and development

What does calcitonin do?

Lowers blood calcium

Where are the parathyroid glands located?

In the neck, posteriorly

What hormone does the parathyroid release?

PTH

What does PTH do?

Raises blood calcium

What hormones are listed for the adrenal gland?

Aldosterone, cortisol, and androgens

What does aldosterone control?

Salt and water balance and blood pressure

What does cortisol control?

Stress, metabolism, and energy

What do androgens control?

Sex hormones

Where is the pineal gland located?

In the brain

What hormone does the pineal gland release?

Melatonin

What does melatonin control?

The sleep/wake cycle

What makes the pancreas an endocrine gland?

It releases hormones directly into the bloodstream

What makes the pancreas an exocrine gland?

It releases digestive enzymes through ducts to help digest food

What are the two major hormones released by the pancreas?

Insulin and glucagon

What cells release insulin?

Beta cells

What cells release glucagon?

Alpha cells

What does insulin do?

Lowers blood glucose