Chemical Signals, Hypothalamus, Pituitary Gland, and Reproduction ( Lecture 3)

Flashcards covering chemical signals, the hypothalamus and pituitary gland, hormone functions, and animal reproduction.

What are the three types of chemical signals?

Autocrines, paracrines, and hormones.

What two major structures are focused on in terms of the endocrine system?

The hypothalamus and the pituitary gland.

What are the two parts of the Pituitary gland?

The anterior and posterior portions.

Which system sends messages that the hypothalamus receives?

The peripheral nervous system.

What is the role of the hypothalamus in the regulatory system?

Receives, integrates, and interprets messages, and sends messages to the pituitary gland.

What role does the pituitary gland play in the endocrine system?

It interprets signals from the hypothalamus and sends out chemical signals to the rest of the body.

What is the anterior portion of the pituitary gland made of?

Endocrine cells.

What is primarily located in the posterior pituitary?

Nerves from the hypothalamus.

What are the two types of neurohormones secreted by hypothalamic neurons?

ADH (antidiuretic hormone) and oxytocin.

What is the function of ADH?

Triggers kidneys to conserve water and causes constriction of peripheral blood vessels to elevate blood pressure.

What is the function of Oxytocin?

Muscle contractions and milk flow from mammary glands- positive feedback loop from the cervix to the Hypothalamus.

What type of signal comes from a nerve?

A neurotransmitter, or neurohormone if going into the blood.

What type of signal comes from an endocrine cell moving into the bloodstream?

Hormone.

What system carries the releasing hormone from the hypothalamus to the anterior pituitary?

The hypophyseal portal blood vessels (portal blood system).

What is a releasing hormone?

A set of instructions from the hypothalamus that tells the endocrine cells of the anterior pituitary what to do.

What is a tropic hormone?

A hormone released from the anterior pituitary that triggers one of the other glands in the body to release a hormone.

What are the 5 releasing hormones from the hypothalamus?

Thyrotropin-releasing hormone (TRH), gonadotropin-releasing hormone, corticotropin-releasing hormone, prolactin-releasing hormone, prolactin-release inhibiting hormone, growth hormone-releasing hormone, and growth hormone release inhibiting hormone

What does thyrotropin released from the anterior pituitary stimulate?

The thyroid gland.

Examples of tropic hormones

Follicle stimulating hormone, Corticotropin and Luteinizing hormone.

What do nontropic hormones from the anterior pituitary affect?

Specific cells throughout the body.

What's the difference between tropic and nontropic hormones?

Tropic hormones trigger endocrine glands to release hormones, while nontropic hormones stimulate specific cells without involving other endocrine glands.

What is the role of thyroxine?

Released from the thyroid glad, it is a hormone that stimulates or causes an increase in a cel's metabolism.

What is the role of calcitonin?

Released from the thyroid gland, it triggers the bones to start incorporating more calcium out of the bloodstream.

What are the releasing hormones?

Instruct the anterior pituitary.

What are the tropic hormones?

Affect one of the other glands in the body.

Explain the process of a short negative feedback loop

Corticotropin is released from the anterior pituitary to affect the adrenal gland. After flooding happens, the corticotropin moves back towards the hypothalamic neurons where it inhibits the production of corticotropin releasing hormone.

What does the thyroid gland release that increases cell metabolism?

Thyroxine.

Explain the process of a long negative feedback loop

It shuts down both the anterior pituitary AND the hypothalamus. So the hormone from the endocrine gland will stop both of those

What are the two types of sex steroids?

Androgens (testosterone) and estrogens/progesterone.

What primarily determines whether the fetus will have male or female genitalia?

The presence or absence of androgens.

What determines gender genetically

Whether there is an X or a Y chromosome (XY = male, XX = female)

Define primary sex characteristics.

Those you are born with. The scrotum and the penis versus the vagina and the labia minora.

Define secondary sex characteristics.

The development of breast tissue in females, or facial hair in males.

What triggers the gonads to release their hormones in primary sex characteristics?

Gonadotropins from the anterior pituitary.

What are the 3 fundamental steps of sexual reproduction?

Gametogenesis, mating, and fertilization.

Define Gametogenesis.

he production of gametes.

Define Fertilization.

The fusing of gametes.

What is the animal reproduction that is considered the equivalent of mitosis?

Binary fission.

What is budding?

A form of asexual reproduction where a new individual grows out of the body of the parent.

What is regeneration?

When body parts are severed and not only can they repair and regrow that part, but the part that was severed can actually repair and grow into an entirely different individual.

What is parthenogenesis?

The development of offspring from unfertilized eggs.

What is another name used for eggs?

Ova.

What are the three requirements of sexual reproduction?

Gametogenesis, mating, and fertilization.

What cell type undergoes mitosis to create spermatocytes?

Spermatogonium.

Where does the first meiotic division occur in males?

In adulthood.

What stem sells do women have when they are born?

Primary Oocytes.

How does fertilzation occur?

Sperm and egg have to recognize the other, enzymes are released to dissolve the jelly coat, and plasma membranes fuse. Additional sperm are shut down, and the egg and sperm nuclei fuse.