BISC 1404 Midterm: Unit 3 Study Guide Chapters 45-51

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Fordham University
Biological Sciences
BISC 1404

CHAPTER 45: HORMONES AND THE ENDOCRINE SYSTEM Hormones • What is a hormone? • signalling molecules secreted in small amounts in one part of an organism and transported to another where they bind to specific receptors and trigger responses in target cells and tissues. • What is the difference between the endocrine and the nervous system? • Endocrine-chemical signalling by hormones • Nervous- networks of neurons that transmit signals along a dedicated pathway • What are different types of intercellular communication within an organism? • Endocrine-release hormones, for long distances • Paracrine- secreting hormones for nearby signalling, short distances • Autocrine- hormones that stimulate the same cell that secretes it • Synaptic- neuron with synapse on cell • Neuroendocrine- neurosecretory cell with synapse at blood vessel • What is a pheromone? • Pheromones- chemicals released by organisms that can affect behavior of other organisms • What are the different types of hormones? • Polypeptides (water soluble), Steroids (lipid soluble), Amines (can be both) derivatives of nucleic acids • How do signal transduction pathways and cellular responses differ in water-soluble and lipid- soluble hormones? • Water soluble receptors in plasma membranes • lipid soluble receptor nucleus or cytoplasm, and need a transport protein when in blood • How can one hormone have multiple effects? • can bind to different receptors • What are the different endocrine glands and which hormones do they secrete? • Pineal Gland - melatonin • Hypothalamus- controls pituitary • Anterior Pituitary- LH, FSH, TSH, Prolactin, Growth hormone • Posterior Pituitary- oxytocin and ADH • Thyroid- thyroid hormone maintains metabolism • Parathyroid- PTH raises blood calcium levels • Adrenal Gland- epinephrine and glucocorticoids • Pancreas- insulin, glucagon • Ovaries- Estrogen, Progesterone • Testes- Androgens Endocrine Signaling • What are examples of simple endocrine and neuroendocrine pathways? How are positive and negative feedback involved? • Endocrine- Simulus → Endocrine cell → Hormone → receptor of target cell → response • ex. secretin secretion in duodenum to elicit bicarbonate release in pancreas • Neuroendocrine- stimulus to neurosensory neuron that triggers neurosecretory cell to release neurohormone which elicits response in target cell • ex oxytocin to smooth muscle mammary glands to release milk • How do the hypothalamus and pituitary glands interact to coordinate the endocrine system? • hypothalamus sends neurosecretory hormones to posterior and anterior pituitary to trigger hormone secretion • List and describe the functions of hormones released by the anterior and posterior pituitary lobes • Anterior- FSH and LSH stimulate ovaries and testes, TSH stimulates thyroid, ACTH stimulates adrenal cortex, Prolactin stimulates mammary glands, Growth Hormone stimulates growth and metabolic function • Posterior- Oxytocin stimulates contractions of smooth muscles in uterus and mammary glands, ADH promotes retention of water in kidneys, influences social behavior and bonding • What is the role of tropic hormones in coordinating endocrine signaling throughout the body? • a hormone that stimulates an endocrine gland to grow and secrete its hormones. (One hormone causes another hormone to do something) Hormonal Regulation of Homeostasis, Development, and Behavior • How do adrenal hormones regulate the stress response? What are the effects of these hormones? • Short term response: epinephrine and norepinephrine triggers increased blood glucose, blood pressure, breathing rate, metabolic rate, and blood flow patterns. • Long term response: glucocorticoids increase blood glucose and partially suppress immune system. mineralocorticoids retain sodium and water in kidneys and increase blood pressure and volume • What are endocrine disruptors? • can increase or decrease normal hormone levels, mimic natural hormones, or alter the natural production of hormones CHAPTER 46: ANIMAL REPRODUCTION Asexual vs. Sexual Reproduction • What is the difference between asexual and sexual reproduction? • Asexual- generation of offspring from 1 parent, no fusion of gametes, genetically identical • Sexual- 2 parents, fusion of gametes into zygotes, offspring have unique combo of DNA • Mechanisms for each? • Asexual: budding( new arise from old) , fission (divide in two), fragmentation (regrowth of lost body part) , parthenogenesis (females produce diploid or haploid offspring from unfertilized egg) • Sexual: external fertilization or internal fertilization • Evolutionary advantages/disadvantages to each? Under which conditions would each be favored? • sexual reproduction must have an advantage to be chosen over asexual like gene shuffling • What is the significance of reproductive cycles and ovulation? • reproduction is energetically costly, related to the changing seasons, cycles controlled by hormones and environment • Ovulation- release of mature eggs at midpoint of cycle • How do fertilization mechanisms, numbers of gametes produced, and parental care affect survival of offspring? • # of surviving offspring are affected by the number of gametes produced, protection of the embryos, and parental care Reproductive Systems and Gametogenesis in Humans • What are gonads? What are the gonads and where are they located in human males and females? • Gonads- organs that produce gametes, males = testes, females = ovaries • Where does gametogenesis occur in males and females? • Happens in testes in males and ovary follicle in females • Describe the processes of spermatogenesis and oogenesis. How are they similar? Different? • Spermatogenesis- primordial germ cells undergo mitosis to become primary spermatocytes which undergo meiosis into early spermatid. These differentiate into mature sperm cells (1 cell = 4 sperm) • Oogenesis- primordial germ cells undergo mitosis into oogonium and then again into primordial oocyte (present at birth). Starting at puberty, meiosis occurs and at secondary oocyte it stops at metaphase II unter sperm enters. It then completes meiosis creating 2 polar bodies and 1 fertilized egg. (1 cell = 1 egg+2 polar bodies) • Spermatogenesis is continuous and occurs during adolescence while oogenesis starts at puberty and ends at menopause. Hormonal Control of Reproduction • Which hormones control the male reproductive system? How are they regulated? • Hypothalamus releases GnRH → Anterior pituitary releases FSH and LH. FSH → sertoli cells (help mature sperm) → promotes spermatogenesis and release Inhibin LH → Leydig cells → testosterone promotes spermatogenesis • Which hormones control female reproductive cycles? How are they regulated? • Describe the ovarian cycle and the uterine/menstrual cycle • Pregnancy and Childbirth • What is implantation? What is pregnancy? • Pregnancy- condition of carrying embryo in uterus • Implantation- fertilized egg connecting to uterus • What is the placenta? Which structure present during early development becomes the placenta? What is the purpose of the placenta? • Placenta- an organ that develops and holds developing embryo after 4 weeks. its the major blood flow from mother to child CHAPTER 47: ANIMAL DEVELOPMENT Embryonic Development • What are the four main stages of embryonic development? • Fertilization, Cleavage (cell division into blastula) , Gastrulation (formation of gastrula), Organogenesis (organ development) Fertilization • Describe the acrosomal and cortical reactions and fast vs. slow blocks to polyspermy • Acrosomal Reactions- in sea urchins, hydrolic enzymes released from acrosome (tip of sperm), enzymes partially digest jelly coat of egg, actin filaments grow from head of sperm to form acrosomal process (binding to receptors on membrane), fusion of plasma membranes • Cortical Reaction- vesicles (cortical granules) in egg fuse with membrane, vesicle contents secreted into space between membrane and surrounding vitelline layer, Enzymes and other molecules from cortical granules lift vitelline layer away from egg and harden it into protective fertilization envelope, Sperm-binding receptors and any attached sperm clipped and released • Fast Block- recognition event between sperm and egg triggers fusion of plasma membranes, sperm nucleus enters egg cytoplasm, ion channels open in eggs membrane, Na+ ions diffuse IN and cause depolarization which changes the charge across the membrane. The depolarization prevents additional sperm from fusing with eggs membrane for one minute • Slow Block- Fertilization envelope prevents additional sperm from fertilizing egg, Block is longer-lasting than fast block • What is the role of calcium ions in the cortical reaction? • changes in calcium concentrations trigger cortical reaction and formation of fertilization envelope. • Binding of sperm to egg activates signal transduction pathways, that cause the ER to release calcium into the egg cytosol • What is egg activation? • Fertilization initiates and speeds up metabolic reactions that bring about onset of embryonic development (activates egg) • increases in Calcium concentration activates egg in addition to triggering cortical reaction • How does fertilization occur in mammals? • Support cells of developing follicle surrounding egg before and after ovulation • Zona Pellucida- extracellular matrix of egg • Acrosomal Reaction- induced by binding of sperm to sperm receptor to facilitate sperm entry (no fast block) • Sperm binding triggers cortical reaction → changes in zona pellucida → slow block to polyspermy Cleavage • What are the main stages and structures of cleavage? • Rapid cell division without cell growth, partitions of cytoplasm of zygote into many smaller cells (blastomeres), formation of blastula, at end of cleavage G1 and G2 phases appear and cell grows • What are different patterns of cleavage displayed by different groups of animals? • Uniform • Asymmetric in distribution of yolk, yolk concentrated towards vegetal pole, away from animal pole, affects where division occurs • Holoblastic- cleavage furrow passes through yolk (us) • Meroblastic- cleavage furrow does not pass all the way through yolk Gastrulation • What is gastrulation? • formation of 3 embryonic germ layers ectoderm (outer layer) mesoderm (middle layer) endoderm (lines digestive tract) • What are the major stages and structures in human gastrulation? • set of cells at or near surface of blastula moves to interior location (called Invagination) • cell layers are established • the archenteron, primitive digestive tube, formed • What are the four extra-embryonic membranes in amniotes, and what is the function of each? • Chorion- functions in gas exchange • Amnion- encloses amniotic fluid • Yolk Sac- provides nutrients • Allantois- disposes of waste products and contributes to gas exchage Organogenesis • What is organogenesis? • Organogenesis- region of embryonic germ layers develop into rudiment organs • What is neurulation? Which major processes and structures are involved? • Neurulation- early steps in formation of vertebrate brain and spinal cord • Neural tube becomes brain and spinal cord. folding takes place Morphogenesis • What is morphogenesis? • Morphogenesis (gastrulation + organogenesis) - cellular and tissue based processes by which animal body takes shape, Involves migration of cell and movements of cell parts Cell Fate • What is fate mapping? • Fate Mapping- determining structures arising from each region of an embryo • What are differentiation and determination? • Differentiation- cells actually becoming the fate (doing the major) • Determination- process by which cells become committed to a particular fate (declaring a major) • What is axis formation? • Anterior, posterior, dorsal, ventral, right, left sides of embryo CHAPTER 48: NEURONS, SYNAPSES, and SIGNALING Neurons • What is the structure of a neuron? • Nucleus, Cell Body, Dendrites, Axon hillock, axon, synaptic terminals with synapses releasing neurotransmitters • What are glia? • non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons • How is information processed? How are sensory, interneurons, and motor neurons involved? • Sensory neurons take in information and send it to the processing center by interneurons for integration and then a signal is sent out by interneurons to motor neurons that elicit an action Membrane Potential • What is membrane potential? • •Difference in charge (voltage) = source of potential energy, Ions unequally distributed between interior and exterior fluid of cells, Cell interior more negative than exterior (membrane potential) • What is resting potential? • Neuron not sending signal = resting, Membrane potential of resting neuron = resting potential, Resting potential = -60 to -80 millivolts (mV) • Which ion channels are involved in membrane potential, and how? • Sodium channel brings sodium inside cell, Potassium channel brings potassium outside cell, Sodium-potassium pump does both (more sodium outside cell and potassium inside cell) • What is the equilibrium potential of an ion? • Equilibrium potential of potassium is negative and sodium is
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