Bio Week 16 Notes
Bio Week 16 Notes BIO 181
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This 8 page Class Notes was uploaded by Ernie on Sunday April 24, 2016. The Class Notes belongs to BIO 181 at Arizona State University taught by Chakravadhanula, Farrokh, Konikoff in Winter2015. Since its upload, it has received 33 views. For similar materials see General Biology 1 in Biochemistry at Arizona State University.
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Date Created: 04/24/16
Bio Lecture Notes 4-18-2016 Endocrine System Endocrine System Collection of organs and cells that secrete chemical signals into the blood Hormone- Chemical signal that circulates through body fluids and affects far cells In low concentrations, but have large effects on cells Last longer than action potentials Different Chemical Signals Same Separated: Autocrine Besides Separated: Paracrine Inside Separated: Endocrine Neurotransmitters: Neural Nerve Inside Separated: Neuroendocrine Autocrine Signals act on the same cell that secretes them Cytokines: Known as cell movers Paracrine Signals Diffuse locally and act on neighboring target cells Cytokines can be an autocrine and a paracrine Endocrine Signals Hormones produced and secreted by specialized cells or glands, carried by blood to distant cells Neural Signals Neurotransmitters diffuse a short distance of presynaptic cell to a postsynaptic cell Bind to membrane receptors and result in change in membrane potential Neuroendocrine Signals Neuroendocrine signals are considered hormones because they are carried by blood to other body fluids and act on distant cells Do not act on at the synapse Hormone Signaling Pathways 1) Endocrine- Sends hormones directly from endocrine cells to effector cells 2) Neuroendocrine- Releases neuroendocrine signals that act directly on effector cells 3) CNS-to-endocrine- Neuroendocrine signals stimulate cells in endocrine system, then is producing an endocrine signal that acts on effector cells This are regulated by negative feedback Endocrine & Nervous Systems Work Together to Regulate Response to a Stimulus Endocrine Glands- Organs that secrete hormones into bloodstream Tissues & Organs that make up the endocrine system vary widely among animals Additional Components Cells in many other organs and tissues secretes hormones even though they are not organized into discrete glands Bio Lecture 4-20-2016 Endocrine System Maintenance of Homeostasis Messages travel from integrators to effectors in the form of hormones Examples 1) Leptin & Energy Reserves 2) ADH, Aldosterone & Electrolyte Balance 3) EPO & Oxygen availability Energy Reserves Homeostasis system regulates triglyceride stores which are energy storage Ob and db Genes Ob Cides for leptin which is a polypeptide hormone Secreted by adipocytes Db gene codes for leptin receptor Blood leptin levels vary with total adipose tissue mass Blood Oxygen Levels When Blood oxygen levels fall it is called hypoxia, or RBC counts are low (Anemia) kidneys release EPO EPO stimulates production of RBC erythrocytes which increases blood viscosity Hormone Regulation Hormone production is directly or indirectly controlled by CNS Physical link between hypothalamus & pituitary is the basis of the connection between CNS & Endocrine System Pituitary Gland secretes growth hormone as well as hormones that regulate production of many others Cortisol exerts feedback inhibition on adreno-corticotropic hormone ACTH release Pituitary & Hypothalamus Developmentally & anatomically the posterior pituitary is an extension of the hypothalamus Hormones produced by other populations of neurosecretory cells in the hypothalamus travel in the blood to the anterior pituitary, where they control the release of pituitary hormones Hormone Target Cells Steroid hormones can cross the plasma membrane easily Lipid soluble so they can cross the plasma membrane and bind to intracellular receptor Model System: Estradiol Peptide & AA derivative hormones must bind to cell surface receptors except thyroid hormones Lipid Insoluble Model System: Epinephrine Epinephrine Triggers a signal transduction cascade Bio Lecture 4-20-2016 Reproductive System Sex Determination Female: XX & Male: XY Females: ZW & Males: ZZ Haplodiploidy Males develop from unfertilized eggs and are haploid Temperature Dependent- Sex is determined by temperature in some reptiles RNA Determines sex in silkworms First Sex determination that doesn’t involve protein Bio Lecture Notes Reproductive System 4-22-2016 Gametogenesis- Sperm or egg meiosis Eggs (oogenesis)- Forms secondary oocyte and a polar body the polar body is not functional, then makes an ootid & another nonfunctioning polar body Sperm (Spermatogenesis)- Starts with diploid & undergoes mitosis, meiosis one makes sperm haploid Mammalian Sperm Sperm are specialized for motility & fusing with an egg cell Both nucleus need to join together in order to return to a haploid state Mammalian Eggs Surrounded by protected structure Fertilization 2 Types External (aquatic animals)- many gametes used and released in water synchronously Internal (Terrestrial animals) Fewer gametes produced sperm goes into female Egg Laying vs Live Birth Oviparous (Egg Bearing) embryo completes development in an egg laid in the environment Viviparous ( Living Bearing) Embryo develops entirely in mothers body Ovoviviparous Offspring develop in mothers body but are nourished by yolk in stored egg Male Reproductive System Morphology Varies among species Male Genitalia shape and size may affect sperm competition Human Male Reproductive Organs 3 Function in Humans 1. Spermatogenesis & Storage 2. Production of accessory fluids 3. Transport and delivery Female Reproductive System Ova are produced in the ovary Ova membrane is bound with haploid nucleus full complement of other organelles and large nutrient supply yolk Human Female Reproductive Organs 2 Functions 1. Production and transport of eggs 2. Development of offspring Sex Hormones Play role in mammalian reproduction Testosterone and estradiol are the gonadal hormones produced by ovaries and testes respectively Puberty Process that leads to sexual maturation Triggered by hormones from hypothalamus and pituitary GnRH is released from the hypothalamus leading to pulses in FSH and LH
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