Chapter 2 Flashcards
What are the two main types of hormonal effects?
Genomic Effects and Nongenomic Effects
Genomic effects involve hormones binding to receptors inside cells and changing gene activity, while nongenomic effects involve hormones acting on receptors outside cells and producing faster behavioral effects.
What is the role of the endocrine, nervous and immune system?
To release hormones, neurotransmitters and cytokines
What are the different types of chemical mediation?
Intracrine, Autocrinem paracrine, Endocrine and Ectocrine
What type of mediation involves chemicals acting within the same cell?
Intracrine Mediation
Intracrine mediation refers to the action of chemicals within the same cell, some of which evolved into hormones or pheromones.
What is autocrine mediation?
Cells release products that act back on themselves (SEE TABLE)
An example is steroid-producing cells that have receptors for their own hormones, or cancer cells
What defines paracrine mediation?
Chemicals released by one cell affect nearby cells (SEE TABLE)
Examples include neurotransmitters like dopamine
What distinguishes endocrine and exocrine/ectocrine mediation?
- Endocrine Mediation
- Hormones are secreted into the bloodstream and travel to distant targets.
- Ex→ Insulin: Secreted by the pancreas, regulates blood glucose levels body-wide
- ex→ adrenaline and thyroid hormones
Exocrine/Ectocrine Mediation
- Substances released externally affect other individuals or organs
- use exocrine glands and have ducts or tubes
- Ex→ Pheromones, human sweat
What is the dual function of the pancreas?
Secretes digestive juices (exocrine) and produces hormones like insulin (endocrine)
The pancreas functions both as an exocrine gland and an endocrine gland (SEE TABLE)
What are the different types of pheromones?
Pheromones-> chemicals signals that communicate with members of same species
Alomones-> chemical signals affecting different species benefiting the sender (skunk spray)
Kairomones-> chemical signals affecting different species benefiting the receiver (human sweat attracting mosquitos)
Synomones-> chemical signals affecting different species benefiting the sender AND receiver (floral scents attracting pollinators)
What are protein/peptide hormones characterized by?
Water-soluble, stored in secretory granules, released through exocytosis
- remove from the blood by degradation or excretion
- reported in biological half-time→ amount of time required to remove half of the hormone from the blood
Examples include insulin and growth hormone.
What is the different between a protein hormone and a peptide hormone?
Protein→ larger in size, long chains of amino acids (more than 50)
- ex: insulin, growth hormone, prolactin
Peptide→ smaller and short chains (fewer than 50)
- oxytocin, vasopressin, glucagon
SEE TABLE
What defines steroid hormones?
Lipid-soluble, not stored, produced and released on demand
- carrier proteins help regulate hormone actions
SEE TABLE
Steroid hormones are derived from cholesterol and bind to carrier proteins in the blood.
What does the lock and key mechanism refer to in hormonal action?
Receptors as specific binding sites and hormones as keys
Hormones bind to receptors with high affinity and specificity.
What are the different endocrine organs and where are they located?
Hypothalamus, pituitary, thyroid, pancreas, adrenal, pineal, gonads and placenta
SEE TABLE
What are the hypothalamic cells responsible for the release of neurohormone into blood vessel of pituitary glands?
Neurosecretory cells→ release of neurohormones into blood vessel of pituitary glands
- structurally similar to neurons BUT function like endocrine glands
- neurohormones→ released into the blood rather than synaptic space, allowing communication between hypothalamus and pituitary gland
These include releasing and inhibiting hormones that regulate pituitary function.
What are the releasing hormones in the hypothalamus
Releasing hormones→ small peptides
- TRH (Thyrotropin-Releasing Hormone)
- GHRH (Growth Hormone-Releasing Hormone)
- GnRH (Gonadotropin-Releasing Hormone)
- MRH (Melanotropin-Releasing Hormone)
- CRH (Corticotropin-Releasing Hormone)
What are the inhibiting hormones in the hypothalamus?
Inhibiting Hormones→ prevent release of specific hormones from the pituitary
- somatostatin (Growth Hormone-Inhibiting Hormone or GHIH)
- GnIH (Gonadotropin-Inhibitory Hormone)
Dopamine→ Acts as a neurohormone in the hypothalamus, inhibiting the release of prolactin (PIH) and melanotropin (MIH) from the anterior pituitary.
What is the role of the hypocretin/orexin in the hypothalamus?
Involved in regulating sleep, metabolic balance, and potentially activating the sympathetic nervous system
What are the primary hormones produced by the anterior pituitary (Adenohypophysis)?
- acidophils→ growth hormone (gH) and prolactin
- basophils→ luteinizing hormone (LH), follicle-stimulating hormone (FSH), and thyroid stimulating hormone (TSH)
These hormones are classified as tropic hormones.
What is the function of oxytocin?
Social behaviors, bonding, and emotional regulation
Oxytocin is linked to decision-making and social cognition.
What are the primary hormones released by the Posterior (Neurohypophysis) Pituitary?
oxytocin and vasopressin
What are the two methods of communicatin between the hypothalamus and the pituitary glands?
Two methods of communication
- Neurohormones via the Portal System→ Neurohormones (releasing hormones) from the hypothalamus reach the anterior pituitary through a specialized blood circuit and release tropic hormones
- Direct Neural Connections→ The hypothalamus also communicates with the posterior pituitary via direct neural pathways
Match hormone in pituitary with homorne needed for release?
SEE TABLE
What is the primary hormone produced by the thyroid gland?
Thyroxine (T4)
T4 is fat-soluble and increases oxidation rates in tissues.
