Exam 1 Flashcards
What is a hormone? How does it differ from a pheromone?
A hormone is a chemical molecule/ a chemical signal between cells/ a chemical messenger
Hormones are chemical signals to communicate with cells in the body, whereas pheromones send chemical signals outside of the body to nearby things
Describe and contrast the different types of hormones. Explain their properties.
Proteins & Peptides
- made of amino acids
- created by pituitary hormones
- bind to membrane receptors
- pre-prohormone gets edited
differences
- peptides don’t cross cell membrane
- proteins have a large amount of amino acid
- peptides have a small amount of amino acid
Monoamine
- class of neurotransmitters that consist of dopamine, norepinephrine, and serotonin
Describe and contrast the different types of hormones. Explain their properties.
Steroid hormones
- either sex or stress hormones
- hormones bind to rece ptors and activate gene expressions (example: testosterone creates facial hair)
- also bind to the DNA and are direct modulators of gene expression
- derived from cholesterol
- fat-based
- crosses cell membranes
- get in any body fluid
- bind to intracellular receptors
- Adrenals (on top of your kidney), gonads, and brain all produce steroid hormones
- Membrance bound receptors also often exist as part of a bigger receptor complex
Describe the mode of production of peptide hormones?
Gene -> mRNA -> pre-pro-hormones (many amino acids) -> hormones (edited to fewer amino acids)
What is vasopressin?
- male focused peptide hormone
- created by the neurohypophysis in the pituitary gland
- 9 amino acids
- anti-dieuretic, helps you save water, can also make males aggressive
- located on the same DNA strand as oxytocin
- activated by drop in blood pressure or increase in temperature
- inhibited by low temp and alcohol
- modulates memory, territorial behavior, aggression, attachment, paternal behavior
What happens after a hormone activates it’s receptors? **
- Peptide hormones and other water-soluble hormones bind to receptors located on the surface of the target cell membrane because they cannot pass through the lipid bilayer.
Steroid hormones, thyroid hormones, and other lipid-soluble hormones pass through the cell membrane and bind to receptors located inside the cell, typically in the cytoplasm or nucleus.
What is a hormone receptor agonist? How does it differ from an antagonist? What is RU486?
- Hormone receptor agonist: a substance that mimics the action of a natural hormone by binding to its receptor and activating it
- Hormone receptor antagonist: a substance that mimics the action of a natural hormone by binding to its receptor and inhibits/ blocks hormone receptors
- RU486 is a progesterone receptor antagonist used to interrupt menstrual cycle and early pregnancies
What is a sterotaxic apparatus?
A stereotaxic device uses a set of three coordinates that when the head is in a fixed position, allows for precise location of brain sections
- could be used to implant substances such as drugs or hormones into the brain
Describe different types of chemical communication
- Autocrine: cell synthesizing and releasing
- message and target cell are the same - Justxcrine: target cell located just next to producing cells
- message travels through a close contact such as a gap junction (junction - justxon) - Paracrine: target cell is a neighbor of producing cell, message diffusing in interstitial fluid throughout tissue
- Endocrine: message released into blood circulation, target cell distant from producing cell
- Synaptic: message released at the synapse
What is the posterior pituitary gland? How does it differ from the anterior pituitary gland?
(Posterior)
- neurohypophysis (neural) (back)
- stores oxytocin and vasopressin that was created by the hypothalamus
- releases vapopressin into blood circulation
- modulation by sex steroids
- large neurons located in the PVN and SON project into the neurohypophysis (posterior) and make synaptic-like contact with the periphery of blood vessels
- neurons also release dopamine in the blood circulation
- neurons also release dopamine in the blood circulation
What is the posterior pituitary gland? How does it differ from the anterior pituitary gland?
(Anterior)
Anterior pituitary gland (adenohypophysis) (front)
- originates from ectoderm
- anterior pituitary gland has the HPA axis and the HPG axis
- understress, AVP and OXY active ACTH release from the anterior pituitary gland
- produces and secretes its own hormones under the regulation of releasing and inhibiting hormones from the hypothalamus
- controlled by the hypothalamus through releasing and inhibiting hormones sent via the portal, the blood vessels connecting the hypothalamus to the anterior pituitary gland
Compare the neurons associated with the anterior and posterior pituitary glands
Posterior
Posterior: neurohypophysis - neurons
- the posterior is directly controlled by neurons from the hypothalamus located in two main regions of the hypothalamus:
the paraventricular nucleus (PVN) and the supraoptic nucleus (SON) - these neurons extend their axons directly into the posterior pituitary where they release hormones into the bloodstream
- the two primary hormones released are oxytocin and vasopressin
Compare the neurons associated with the anterior and posterior pituitary glands
Anterior
Anterior: front: adenohypophysis - ectoderm
- the anterior pituitary is regulated by hormones secreted by neurons in the hypothalamus
- these neurons do not directly connect to the anterior pituitary
- instead, they secrete releasing or inhibiting hormones into the portal system, the specialized network of blood vessels that transport these hormones to the anterior pituitary
Describe the hormones of the anterior pituitary gland
Anterior: front: adenohypophysis - ectoderm
TRH: stimulates the release of TSH from the anterior pituitary
GnRH: stimulates the release of FSH and LH
CRH: stimulates the release of ACTH
GHRH: stimulates the release of GH
GHIH: inhibits the release of GH and TSH
Dopamine: Prolactin-inhibiting hormones (PIH) inhibits the release of prolactin (PRL)
