Lecture 15: Hormone Structure and Action Flashcards
What is autocrine communication?
Chemical released by cell affects its own activity
What is neurocrine (synaptic) communication?
Chemical released by neuron diffuses across synaptic cleft and affects postsynaptic membrane
What is paracrine communication?
Chemical released into extracellular environment and affects nearby target cells
What is endocrine (hormone) communication?
Chemical released into bloodstream and selectively affects (distant) organs
What is pheromone communication?
Chemicals released into external environment and affects conspecifics
What is allomone communication?
Chemicals released into external environment and affects heterospecifics
What are hormones?
- Bioregulators of the endocrine system
- Secreted by specialised cells directly into the blood
- Selectively act on target cells
What is the primary function of endocrine signals?
To regulate physiological processes by transmitting hormones through the bloodstream to target organs or tissues.
How are endocrine signals different from neural signals?
Endocrine signals are transmitted through the bloodstream via hormones, while neural signals are transmitted through neurons via electrical impulses.
What are hormones in the context of the endocrine system?
Chemical messengers secreted by endocrine glands that travel through the bloodstream to regulate target organs or tissues.
What is the role of receptors in the transmission of endocrine signals?
Receptors on target cells bind to specific hormones, triggering a cellular response.
How do water-soluble hormones, like peptides and amines, typically signal target cells?
They bind to receptors on the cell surface, activating signal transduction pathways inside the cell.
How do lipid-soluble hormones, like steroids, typically signal target cells?
They pass through the cell membrane and bind to intracellular receptors, affecting gene expression directly.
What is the role of the hypothalamus in the endocrine system?
The hypothalamus regulates the release of hormones from the pituitary gland, influencing various endocrine functions throughout the body.
What is the significance of the pituitary gland in the transmission of endocrine signals?
The pituitary gland, often called the “master gland,” secretes hormones that regulate other endocrine glands, such as the thyroid and adrenal glands.
How does negative feedback work in the endocrine system?
Negative feedback loops help maintain homeostasis by reducing the release of hormones when levels are sufficiently high, thus preventing overproduction.
What is the role of the thyroid hormone in regulating metabolic processes?
Thyroid hormones regulate metabolism by influencing the rate at which cells convert nutrients into energy.
How do endocrine signals contribute to stress response?
Endocrine signals, particularly the release of cortisol from the adrenal glands, help manage the body’s response to stress by increasing glucose availability and suppressing non-essential functions.
What is the function of insulin in the endocrine system?
Insulin, produced by the pancreas, helps regulate blood sugar levels by facilitating the uptake of glucose into cells for energy.
What are the three types of hormones?
- Protein hormones
- Amine hormones
- Steroid hormones
What are protein hormones made up of?
A chain of amino acids
- peptide hormones have a short chain
What are three examples of protein hormones for social bonding and parental care?
- Oxytocin
- Vasopressin
- Prolactin
What are two protein hormones for metabolism?
- Insulin
- Glucagon
What are two protein hormones for reproduction?
- Luteinizing hormone (LH)
- Follicle-stimulating hormone (FSH)