chapter 45

type 1 diabetes

(insulin dependent diabetes) -An autoimmune disorder in which the immune system destroys the beta cells of the pancreas -Appears during childhood -destroys the ability to produce insulin

type 2 diabetes

(non-insulin dependent diabetes) -Characterized by a failure of target cells to respond normally to insulin (Insulin is produced, but target cells fail to take up glucose from the blood, and blood glucose levels remain elevated) -Excess body weight and lack of exercise significantly increases the risk

Why would energy be required in this response? Why would the cardiovascular system be involved? Be specific!

-part 1: they can be used by body cells as fuel in response to short term stress -part 2: they increase heart rate and stroke volume and dilate the bronchioles in the lungs, actions that raise the rate of oxygen delivery to body cells. For this reason, doctors may prescribe epinephrine as a heart stimulant or to open the airways during an asthma attack. The overall effect is to shunt blood away from the skin, digestive organs, and kidneys, while increasing the blood supply to the heart, brain, and skeletal muscles.

Briefly, what does ADH stand for and what function does it serve?

-stands for antidiuretic hormone -regulates kidney function(increases water retention in the kidneys and helps maintain normal blood osmolarity)

What are the names of their two parts? Which body system controls the production of epinephrine? What structure is the adrenal gland similar to? Does this surprise you?

-the adrenal medulla and the adrenal cortex -the adrenal medulla -the pituitary gland; no(they are both a fused endocrine and neuroendocrine gland)

Signals from the hypothalamus travel directly to the pituitary gland, which is divided into two sections, the posterior pituitary and the anterior pituitary. (They used to be two separate glands that were fused into one, which explains their very different actions). Which part is considered a direct extension of the hypothalamus? Which part is considered an endocrine gland?

-the posterior pituitary is the direct extension of the hypothalamus; hypothalamic axons that reach into the posterior pituitary secrete neurohormones synthesized in the hypothalamus. -the anterior pituitary is an endocrine gland that synthesizes and secretes hormones in response to hormones from the hypothalamus

(testosterone)Review this animation (link provided below) to be sure you understand and can explain this pathway. BE PATIENT as each section takes a few seconds to load:

1. When the level of testosterone in the blood is low, the hypothalamus secretes a releasing hormone (GnRH) which acts on cells in the anterior pituitary 2. In response, the anterior pituitary secretes LH and FSH, which act on cells in the testes 3. LH prompts the Leydig cells to produce and secrete testosterone 4. Sertoli cells bind FSH and testosterone (they function in spermatogenesis at puberty) 5. Increased testosterone levels stimulate the formation and development of sperm 6. High testosterone levels trigger a negative feedback mechanism 7. The testosterone acts on the hypothalamus to inhibit the secretion of GnRH 8. Similarly, a high sperm count induces Sertoli cells to secrete inhibit 9. This hormone inhibits the secretion of GnRH and LH(In this way, hormones are maintained at the optimal levels for sperm formation)

endocrine gland

A ductless gland that secretes hormones directly into the interstitial fluid, from which they diffuse into the bloodstream ex: thyroid glands

Melatonin

A hormone that is secreted by the pineal gland and that is involved in the regulation of biological rhythms and sleep

Neurotransmitters

A molecule that is released from the synaptic terminal of a neuron at a chemical synapse, diffuses across the synaptic cleft, and binds to the postsynaptic cell, triggering a response. Ex: Aspartate

local regulators

A secreted molecule that influences cells near where it is secreted. Ex: cytokines

Pineal Gland

A small gland on the dorsal surface of the vertebrate forebrain that secretes the hormone melatonin

testosterone

A steroid hormone required for development of the male reproductive system, spermatogenesis, and male secondary sex characteristics

Progesterone

A steroid hormone that prepares the uterus for pregnancy

estradiol

A steroid hormone that stimulates the development and maintenance of the female reproductive system and secondary sex characteristics

Androgen

Any steroid hormone that stimulates the development and maintenance of the male reproductive system and secondary sex characteristics (ex: testosterone)

progestin

Any steroid hormone with progesterone-like activity

estrogen

Any steroid hormone, such as estradiol, that stimulates the development and maintenance of the female reproductive system and secondary sex characteristics

Why does a hormone elicit a response only with target cells?

Because then the hormone would go to all the cells and that is unnecessary.

lipid soluble: Mode of travel in bloodstream

Bind to transport proteins that keep them soluble

lipid soluble: Location of receptors

Cytoplasm or nucleus

lipid soluble: Method of secretion

Diffuse out across the membranes of endocrine cells

lipid soluble: examples

Estrogen

ex of tropic hormones and what it regulates

FSH/LH--> testes, TSH--> thyroid, ACTH--> adrenal cortex

What sex would all mammals be without testosterone?

Females, because testosterone promotes development of male reproductive structures.

exocrine gland

Have ducts that carry secreted substances onto body surfaces or into body cavities ex: salivary glands

On the AP Biology exam, you will be expected to explain a feedback loop. Use this figure below to explain the control of blood glucose by insulin and glucagon. This is a commonly used example, and one you should be able to label from Fig. 41.21.

If the blood glucose level rises: beta cells of the pancreas secrete insulin into the blood. Insulin enhances the transport of glucose into body cells and stimulates the liver to store glucose as glycogen, thus lowering the blood glucose levels, and the levels return to normal. If the blood glucose level falls: alpha cells of the pancreas secrete the hormone glucagon into the blood. Glucagon promotes the breakdown of glycogen in the liver and the release of glucose into the blood. The blood glucose level rises, returning the levels to normal.

What does oxytocin do? Why is unique about the feedback loop used with this hormone in connection with in giving birth?

In female mammals, oxytocin controls milk secretion by the mammary glands and regulates uterine contractions during birthing. It also has target in the brain, where it influences behaviors related to maternal care, pair bonding, and sexual activity.

hormone

In multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the organism, changing the target cells' functioning.

hormones

In multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the organism, changing the target cells' functioning. Ex: tryptophan

Where is epinephrine produced?

In the adrenal glands (adrenal medulla)

What are three actions of epinephrine?

Increase the rate of glycogen breakdown in the liver and skeletal muscles

When exposed to fear, list three responses your body may instantly perform for "fight or flight.

Increased blood pressure, breathing rate, and metabolic rate

How is oxytocin an example of a hormone that is under positive regulation?

It is a neurohormone that causes mammary glands to secrete milk. the more stimulation the more oxytocin created.

Where are the adrenal glands found?

On top of the kidneys

What is a simple endocrine pathway? Write down the pathway from endocrine cell to target cell below. What type of feedback loop is this?

Simple endocrine pathway: endocrine cells respond directly to an internal or environmental stimulus by secreting a particular hormone. -The hormone travels in the bloodstream to target cells, where it interacts with its specific receptors. -Negative feedback

What is a simple neuroendocrine pathway? What type of feedback loop is this?

Simple neuroendocrine pathway: The stimulus is received by a sensory neuron, which stimulates a neurosecretory call. The neurosecretory cell then secretes a neurohormone, which diffuses into the bloodstream and travels to target cells -Positive feedback loop

what endocrine gland secretes epinephrine?

The adrenal glands (located atop your kidneys)

Neurosecretory cells of the hypothalamus make and secrete which two hormones?

The antidiuretic hormone (ADH) and oxytocin

Where are the receptors for the water-soluble proteins found? Explain this difference for the two types of hormones.

The receptors are found in the plasma membrane. (while the receptors for lipid soluble proteins are found in the cytoplasm or nucleus.)

The anterior pituitary can release gonadotropins, an intermediate hormone, which prompt the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). What structures do these two hormones act on?

The testes or ovaries

Recall that target cells have receptors for specific hormones (ligands). Where are the receptors for lipid-soluble hormones found? Study Fig. 45.7.

They are found in the cytosol prior to binding to a hormone. When it binds to its cytosolic receptor, a hormone receptor complex forms, which moves into the nucleus.

Describe the role of the nervous system in initiating this response for epinephrine. How does this differ from other hormones you have already learned about?

They function as neurotransmitters (Sensory nerve cells pass the perception of a threat, or stress, from the environment to the hypothalamus in the brain. Neurosecretory cells in the hypothalamus transmit a signal to the pituitary gland inciting cells there to release a chemical messenger into the bloodstream. Simultaneously, the hypothalamus transmits a nerve signal down the spinal cord. Both the chemical messenger and nerve impulse will travel to the same destination, the adrenal gland.)

What occurs in diabetes mellitus?

This is caused by a deficiency of insulin or a decreased response to insulin in target tissues. Blood glucose levels rise, but cells are unable to take up enough glucose to meet metabolic needs. Instead, fat becomes the main substrate for cellular respiration.

Which type of diabetes is correlated with obesity?

Type 2

biorhythms

a recurring cycle in the physiology or functioning of an organism, such as the daily cycle of sleeping and waking.

What is the common name for epinephrine?

adrenaline

water soluble: Location of receptors

cell surface receptors (plasma membrane)

Pheromones Study Fig. 45.3.

chemicals that are released into the external environment ex: asian army ants follow a pheromone-marked trail as they carry pupae and larvae to a new nest site

The body has two long-distance regulating systems. Which involves chemical signals by Hormones?

endocrine system

The hypothalamus is very involved in the regulation of the endocrine system. Is the hypothalamus considered part of the nervous system or the endocrine system?

endocrine system

water soluble: examples

epinephrine

water soluble: Method of secretion

exocytosis

tropic hormones

hormones (many from pituitary) that regulate the function of other endocrine glands or cells.

What are the two intracellular responses in the liver to epinephrine? How do these help the body deal with short-term stress?

inhibition of glycogen synthesis, promotion of glycogen breakdown (release glucose into bloodstream)

Is testosterone a positive or negative feedback loop?

negative feedback

glucagon is secreted by + action by which cells

pancreas alpha cells

insulin is secreted by + action by which cells

pancreas; beta pancreas cells

Expect a free response on the effects of epinephrine.

the effects brought on by a hormone can vary if the target cells differ in the mlcs that receive, transduce, or respond to that hormone. vary in receptors or signal transduction pathways.

What is the other major communication and control system?

the nervous system

water soluble: Mode of travel in bloodstream

travel freely