Chapter 45 Outline - Summary Campbell Biology PDF

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Chapter 45 outline of Campbell Biology outlining the endocrine system....

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Chapter 45: Endocrine system - Animal cells use chemical signals - nervous system -> Neurons - endocrine system -> hormones a)

Hormones: - secreted into extracellular fluid and circulates in blood -> communicates regulatory messages - hormones influence many things such as sex, reproduction as well as the physiological response in maintaining equilibrium (restoring blood sugar levels) - each hormone -> specific receptor - endocrine system utilizes chemical signaling - nervous system is made up of neurons that regulate neurons, muscle cells and endocrine cells - nervous system -> can regulate release of hormones (endocrine and nervous are often overlapping)

b)

THREE TYPES based on solubility properties: - Peptide: composed of strings of amino acids, includes proteins and small polypeptides (water soluble) - Amine: Small molecules synthesized from single amino acid molecules (water solutble) - Steroid: made from cholesterol (fat) and consists of 4 ring structures

c)

Cellular Hormone Response Pathways - Hormone secretes cell -> hormone travels in bloodstream -> reached receptor protein of target cell - Water soluble and lipid soluble hormones differ in pathway water-soluble: can NOT diffuse into the membrane and secreted by exocytosis -> receptor protein is OUTSIDE the cell - extracellular response into intracellular response -> signal transduction - consider epinephrine -> amine hormone that binds to G protein-couple receptor in plasma membrane of target cells -> triggers cascade of events of cyclic AMP (cAMP) -> activated protein kinase A -> activates enzyme used for glycogen breakdown and inactivates glycogen synthesis -> more fuel Lipid-soluble: CAN diffuse through membrane -> leaves through the membrane and received through membrane - intracellular receptors perform the transduction of a signal WITHIN the target cell - Steroid hormone receptors usually located in cytosol

- after the binding, the receptor will MOVE IN to the nucleus and alters transcription of particular genes by interacting with specific DNA- binding protein or response element in DNA d)

Chemical signaling: - can be over a range of distance (like small, mid, long) LOCAL (short): cells communicate to neighboring cells via paracrine or autocrine signaling - cells produce and secret local regulators and they reach their target by diffusion - blood pressure regulation, nervous system function and reproduction - paracrine -> neighboring cell - autocrine -> itself - prostaglandin: local regulator that involved in inflammation, aspirin blocks it ACROSS: neurons use axons and release neurotransmitters to communicate across synapses Synaptic and Neuroendocrine signaling - use of neurons using junctions called synapses - transmission of neurotransmitters and binds to receptor cells LONG: Endocrine cells secrete hormones that can circulate in the blood and travel long distances - Maintains homeostasis by regulating blood pressure and volume, energy metabolism, solute concentration, responses to environmental stimuli, growth and development, and physical and behavioral changes OUT: Pheromones that can be used to communicate information to other members of the same species, warn of predators, marking territories

e)

Specificity of hormones same hormone can have different effects on target cells due to multiple factors - different receptors - different signal transduction pathway ex. epinephrine triggers range of effects that form the "fight or flight" response

f)

Feedback regulation Negative feedback: reduces initial stimulus, preventing excess activity - helps restore a preexisting state -> typically homeostasis Positive feedback: reinforces a stimulus to produce an even greater response g) Coordination of endocrine and nervous systems Simple endocrine pathway: endocrine cells reponse by secreting hormone -> reception

Simple neuroendocrine pathway: stimulus received by sensory neuron instead of tissue -> secretion of neurohormone Control of development in invertebrates (using a moth example) - larva must periodically molt -> endocrine pathyway begins in the larval brain - Neurosecretory cells procude PTTH - PTTH 0-> prothroacis gland -> release of ecdysteriod -> sucessful molt - Ecdysterioud can cause either molting or metamorphosis -> determined by juvenile hormone (JH) - high (JH), ecdysteroid simulates molting - low (JH), ecdysteriod simulates formation of pupa Control of development in vertebrates - relies on the HYPOTHALAMUS - hypothalamus receives information from nerves and initiates neuroendocrine signaling - hypothalamus receives info about seasonal changes -> regulates reproductive hormone for breeding season - hypothalamus signal -> pituitary gland (lima bean lookin ass) - posterior AND anterior - posterior just releases neurohormones created by hypothalamus - anterior makes AND secretes hormones based on hormones secreted by hypo Anterior Pituitary Hormone: - controls diverse processes including metabolism, osmoregulation, and reproduction - hypothalamus controls the release of all anterior pituitary hormones - hypothalamic hormone regulates release of one or more hormone by anterior pituitary (called releasing or inhibiting hormone) - neuroendocine pathways -> hormone cascade (signal to brain -> hypothalamus -> anterior pituitary hormone -> endocrine organ) Thyroid stimulating hormone (TSH) - maintains blood pressure, heart rate and muscle tone - too little thyroid -> hypothalamus secretes TRH -> anterior pituitary secretes thyrotropin aka TSH - TSH simulates thyroid gland -> thyroid hormone Growth hormone (GH) - acts on muscle and bones to simulate growth h) Parathyroid hormone and vitamin D: control of blood calcium - (CA2+) are essential to normal functioning of all cells -> control of it in bloodstream is vital - parathyroid gland regulates it - when blood Ca levels drop, glands release parathyroid hormone - PTH raises level of blood Ca through bones, kidneys and indirectly intestines

i) Adrenal hormones: response to stress - two adrenal glands: adrenal medulla(central) and adrenal cortex (outer) Adrenal Medulla: - "makes" hormones - secretes epinephrine and norepinephrine Adrenal Coretex: - active under stressful conditions - produces glucocorticoids...