Chapter 12: Animal Systems and Homeostasis Part 5/6
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Created by:
kyouS on March 2, 2011
Subjects:
ap biology, animal systems and homeostasis
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100 terms
Terms | Definitions |
|---|---|
 corpus luteum | structure that forms from the developing ruptured follicle that produces progesterone |
| endometrium | inner lining of the uterus necessary for fetus development |
| estrogens | steroid hormones involved in development and maintenance of female secondary sex characteristics and in controlling the reproductive cycle |
| follicle | structure in the ovary that secretes estrogens and houses the developing ovum |
| follicle-stimulating hormone | (FSH) hormone released from the pituitary gland that stimulates growth of the follicle |
| gonadotropin-releasing hormone | (GnRH) hormone that is produced by the hypothalamus that stimulates the pituitary gland to secrete gonadotropin |
| luteinizing hormone | (LH) hormone produced by the pituitary gland that stimulates the ruptured follicle to develop into the corpus luteum |
| progesterone | steroid hormone that promotes uterine lining growth |
| by convention, when refering to the mestrual cycle, day 0 is... | the first day of menstrual flow |
| follicle stage | day 0 - day 12 |
| ovulation | day 12 - day 14 |
| luteal phase | day 14 - day 28 |
| by about what day (0-28), does the corpus luteum start to disintegrate? | day 22 |
| what two hormones operate negative feedback loop with hypothalamus and pituitary gland concerning the menstrual cycle? | progesterone and estrogen |
| progesterone and estrogen in combination signal hypothalamus and pituitary gland to what (negative feedback loop)? | reduce production of FSH and LH (which in turn, causes estrogen and progesterone levels to decline) |
| how does the level of estrogen affect the secretion of FSH and LH? | in small quantities, estrogen inhibits the secretion of FSH and LH; high levels stimulate the production of FSH and especially LH |
| in the event of conception, the fetus produces what hormone to maintain the uterine lining necessary for its development? | human chorionic gonadotropin (HCG), an LH mimic |
| events of the menstrual cycle | (1) hypothalamus produces gonadotropin-releasing hormone (GnRH), (2) GnRH stimulates pituitary gland, (3) pituitary gland produces follicle stimulating hormone (FSH) and lutenizing hormone (LH), (4) FSH stimulates follicle growth (causes follicle to take up water), (5) as follicle grows, it produces estrogen and its number of LH receptors increases, (6) estrogen stimulates production of FSH and esp. LH, as well as build-up of endometrium, (7) follicle is stimulated to release egg (ovulation) by surge in LH levels, (8) after follicle ruptures, LH stimulates follicle to develop into corpus luteum, (9) luteum produces progesterone, (10) progesterone and estrogen operate negative feedback loop with hypothalamus and pituitary gland, unless conception occurs |
| nervous system | system of cells, tissues, and organs that regulates the body's responses to internal and external stimuli |
| two major parts of nervous system | (1) central nervous system, (2) peripheral nervous system |
| central nervous system | (CNS) includes the brain and spinal cord |
| peripheral nervous system | (PNS) consists of sensory and motor nerves connected to the central nervous system |
| two parts of the peripheral nervous system | (1) sensory nerves, (2) motor nerves |
| sensory nerves | receive sensory input |
| motor nerves | deliver motor output |
| neuron | (nerve cell) (1) functional unit of the nervous system, (2) contains all of the organelles found in a typical eukaryotic cell, (3) structure follows its function, which is to conduct electrical impulses |
| major classes of neurons | (1) sensory neurons, (2) interneurons, (3) motor neurons |
| sensory neurons | (1) function is to receive signals from the environment, (2) structure of the neurons' dendrites depends on their function |
| interneurons | (1) serves as a link between sensory and motor neurons, (2) structure allows impulses to be sent to different locations, (3) do not generally have the long axons associated with motor and sensory neurons because they transmit information over much smaller distance |
| motor neurons | cells that convey a message from the central nervous system to effectors, the muscles or gland cells that carry out the actual response |
| parts of the neuron | (1) cell body, (2) dendrites, (3) axon, (4) terminal branches, (5) synaptic terminals |
| dendrites | extensions from a neuron that receives and carries nerve impulses toward the cell body |
| axon | (1) long extension from a neuron that carries nerve impulses away from the neuron, (2) are encircled by specialized cells called Schwann cells, which produces a myelin sheath |
| myelin sheath | (1) formed from Schwann cells wrapped around an axon, (2) prevents ion exchange, (3) causes action potentials to travel from node to node rather than along the whole length of the axon |
| terminal branches | (aka end brushes) are at the end of a motor nerve (aka efferent nerve) and are in very close proximity to the muscle fibers |
| synaptic terminals | (1) are situated close to the dendrites of adjoining neurons (are not physically connected to the dendrites), (2) are able to transmit an electrical impulse across the synaptic cleft |
| synapse | (aka synaptic cleft) space between the dendrite of one neuron and the axon of another neuron |
| reflex | (1) inborn, automatic response, (2) can serve as self-protective measures |
| impulse | (1) an electrical signal involving the flow of ions, (2) is sent down a neuron through a series of electrochemical changes, (3) some impulses inhibit (cause hyperpolarization) rather than excite (cause depolarization); for example, acetylcholine excites skeletal muscles while it inhibits smooth muscles |
| voltage | a difference in potenial [energy] |
| voltage gradient | is set up by a difference in charge due to ion concentration across the membrane of a neuron |
| voltage difference | (aka membrane potential {MP}) (1) the difference in charge between the inside of a cell and its exterior, (2) the voltage measured across the plasma membrane, (3) generally in the range of −50 to −100 in animal cells at rest |
| typical voltage difference across the membrane of a resting neuron (resting potential in millivolts) | approx. -70 millivolts |
| what ions are present inside and outside the membrane of a resting neuron? | (1) Na+ (mostly present outside of membrane), (2) K+ (mostly present inside of membrane), (3) Cl- (mostly present outside of membrane) |
| the negative charge on the inside of the neuron is mostly maintained by... | large negatively-charged proteins |
| what mechanism helps maintain proper balance of the ion concentration (Na+, K+, Cl-) across the neuron membrane? | sodium-potassium ATP pump {Na-K-ATP-p} |
| depolarization (in neurons) | {DPOL} (1) an electrical state that takes place when the inside of a cell is made less negative relative to the outside than at the resting potential, (2) can be triggered by a stimulus on the receptors of the nerve cell, (3) leads to an action potential |
| action potential | {AP} (1) a rapid change in the membrane potential of an excitable cell, (2) begin as an electrical signal, which is then converted to a chemical signal in the form of a neurotransmitter released at the synaptic terminal. Upon binding to the postsynaptic cell, the signal is converted back to an electrical signal in the form of an action potential |
| stimuli are conducted down the axon of the neuron to the synaptic terminal by... | sequential depolarizations and action potentials |
| threshold potential | {TP} the membrane potential (voltage) at which the voltage-gated ion channels open (-55 to -50 mV) |
| voltage-gated ion channels | (1) passageways made of protein that allows ions to enter and exit the cell under certain conditions, (2) control the passage of Na+ and K+ into and out of the cell, allowing for impulse transmission, (3) are either all completely open or all completely closed |
| describe the three main events of the excitation of a neuron | (1) resting phase/state {RP/RS}, (2) DPOL, (3) repolarization {RPOL} |
| describe the process of the excitation of a neuron | (1) neuron is in RP, (2) neuron reaches TP; Na+ channels open, allowing Na+ to rush in (DPOL); influx of Na+ causes MP to rise sharply (interior becomes more +), (3) DPOL of one region of a neuron tiggers DPOL of adjacent regions, (4) as MP peaks, inactivation gates close, preventing further ion flow into cell, (5) at approx. same time as inactivation gates close, K+ gates open slowly allowing K+ to flow out of cell (RPOL), (6) as K+ gates close slowly, MP continues to decrease below RS (hyperpolarization (HPOL)), (7) Na-K-ATP-p restore MP to its RS during refractory period |
| how long does an impulse take from the beginning of DPOL to the end of HPOL (milliseconds)? | 5-7 milliseconds |
| why do myelinated neurons transmit signals more rapidly than non-myelinated neurons? | myelin sheath allows for saltatory propogation which results in a faster impulse (Schwann cells limit the regions on an axon where action potentials can occur) |
| presynaptic membrane/terminal | {PRESYN-} the end of an axon, where neurotransmitter molecules are stored and released |
| postsynaptic membrane/terminal | {POSTSYN-} membrane of the cell on the receiving end of a synapse |
| where are signals transferred from one neuron to the next? | across a synapse |
| neurotransmitters | {NTR} (1) transmit impulses, (2) many different types, such as acetylcholine and endorphins, (3) are found in vesicles in neurons, (4) degrade rapidly |
| neurotransmitters enter the synaptic cleft by... | exocytosis triggered by a rise in cytoplasmic Ca2+ concentrations |
| describe the process of communication across neuron synapses | (1) as impulse reaches PRESYN-terminal, the AP triggers an influx of Ca+2, (2) influx of Ca+2 stimulates vesicles to fuse with PRESYN-membrane and release their contents (NTRs) into synapse, (3) NTRs bind to protein receptors on POSTSYN-membrane and cause them to open, allowing ions to pass through, (4) once ions pass through POSTSYN-membrane, there is a change in MP, (5) NTRs are quickly degraded causing ion channels to close |
| endorphin | neurotransmitter that acts as a natural painkiller |
| drugs that mimic a natural stimulatory NTRs have the effect of | increasing the stimulation of those neurons above their baseline level |
| what is the most primitive animal, and has no nervous system? | sponge |
| what animal has the most primitive nervous system, which is a network of nerves between its two cell layers? | cnidarians |
| cephalization | (1) formation of a brain and sense organs in the anterior portion of an animal, (2) had important implications for evolution of many systems including the digestive system, circulatory system, and especially the nervous system |
| ganglion | an aggregation of nerves external to the brain or spinal cord |
| brain | (1) a concentration of ganglia in one location of an animal's body, usually the head, (2) two main functions: process nervous signals, relay information, (3) divided into two hemispheres |
| specific functions of the brain | (1) sensory interpretation, (2) reflex actions, (3) thought, (4) coordination, (5) memory, (6) emotions, (7) linkage to other organ systems |
| major parts of brain | (1) cerebrum, (2) cerebellum, (3) brain stem |
| parts of the brain stem | (1) medulla oblongata, (2) pons, (3) mesencephalon (midbrain), (4) diencephalon |
| medulla oblongata | (1) relays visual and sensory information to the thalamus, (2) controls autonomic functions such as swallowing, breathing, vomiting |
| autonomic | describes a body function that occurs automatically |
| pons | (1) relays information to the cerebellum, (2) relays information to the thalamus, which relays information to the cerebrum, (3) controls some autonomic functions like breathing, (4) located above the medulla oblongata |
| mesencephalon | (aka midbrain) (1) relays visual and auditory information, (2) maintains consciousness, (3) located above the pons |
| diencephalon | (1) two parts: thalamus and hypothalamus, (2) located above the mesencephalon |
| thalamus | relays information to the cerebrum |
| hypothalamus | (1) maintains constant body temperature, (2) controls hunger, thirst, mating behavior, sexual response, and pleasure, (3) acts as a link to the endocrine system, (4) controls circadian rhythm |
| cerebellum | (1) controls movement coordination, (2) senses positions of joints, senses lengths of muscles, makes action smooth, and maintains equilibrium |
| cerebrum | (1) part of the brain associated wirh intellect, (2) divided into lobes that have specialized functions |
| cerebral cortex | (1) contains most of the brain's activity, (2) the front portion of the brain, about 5 mm deep, about 80% of mass of human brain |
| basal nuclei | (1) centers of motor coordination, (2) degeneration associated with Parkinson's disease |
| corpus callosum | (1) connects the left and right hemispheres, (2) may be associated with autism |
| lobes of the cerebrum | (1) frontal lobe, (2) occipital lobe, (3) temporal lobe, (4) parietal lobe |
| frontal lobe | specialized functions: voluntary centers, speech centers |
| occipital lobe | specialized functions: vision centers |
| temporal lobe | specialized functions: olfactory centers, auditory centers |
| parietal lobe | specialized functions: sensory cortex, speech centers, reading |
| limbic system | (1) primitive part of the brain, (2) controls emotions and memory, (3) includes regions of the thalamus, hypothalamus, cerebral cortex, basal nuclei, and hippocampus |
| human motion is the result of... | the alternating contraction of opposing muscles attached to their bones |
| sliding filament model of muscle contraction | model of muscle contraction in which muscle filaments slide past each other causing a shortening of the sarcomere and contraction of the muscle |
| neuromuscular junction | region where neuron and muscle meet |
| muscles | (1) are made up of bundles of muscle fibers (fascicles), (2) require a nerve stimulus in order to contract, (3) basic functional unit is the sarcomere, (4) work in opposable pairs (one muscle contracts to move a limb one way; a second muscle must act in opposition to the first muscle to forcibly move a limb the other way), (5) muscles only apply a force through contraction (they cannot apply a force through extension) |
| muscle fibers | (1) make up muscles, (2) each fiber is a multinucleated cell, which contains numerous miyofibrils, (3) muscle fibers are bundled into fascicles |
| miyofibrils | (1) enable muscle fiber cells to contract, (2) bundle of thick (myosin) and thin (actin) filaments found within a muscle fiber, (3) has divisions/units that are called sarcomeres |
| actin | globular protein that forms chains that make up thin filaments found in muscle |
| myosin | (1) the protein making up the thick filament of the myofibril, (2) has small appendages called myosin heads that attach to the thin filament (actin) during muscle contraction |
| myosin head | region sticking out of a thick filament that binds to actin filaments during muscular contraction |
| sarcomere | (1) basic functional unit of the muscle, (2) repeating contractile unit that makes up muscles, (3) a group of overlapping actin and myosin filaments bordered by Z lines |
| Z lines | dark lines that make up the borders of sarcomere |
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