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47 Cards in this Set
- Front
- Back
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Nervous system - structural types of neurons: pseudounipolar |
Just one extension, an axon Cell body is to one side of axon Most sensory neurons (carry messages to spinal cord) |
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Ethics |
Voluntary participation: not be pressured to take part Informed consent: fully informed on objectives, procedures, possible risks + potential benefits No risk of harm: no risk of physical or psychological harm Confidentiality: identities of participants will not be revealed except to people directly involved in study |
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Use of animals in research |
Needs to be valid, humane, justifiable and considerate |
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Variables |
IV: factor being investigated (changed) DV: factor responding to change in IV (measuring) CV: factors kept the same UV: variables not kept the same for control + experimental group but overlooked by researcher |
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Repetition vs replication |
Repetition: doing the same experiment many times Replication: having a number of identical experiments running together at the same time |
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Validity |
Experiment tests what it is supposed to test Can be invalid if there are uncontrolled variables |
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Accuracy |
How close the data is to the exact value |
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Reliability |
Extent to which an experiment gives same result each time it is performed Measuring instruments should also be reliable |
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Endocrine - definition |
Influences activity of cells by release of chemical messengers (hormones) Manages homeostasis - ensures fluid of cells is at optimum concentration, constant temp and optimum pressure |
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Exocrine glands vs endocrine glands |
Exocrine glands: secrete into a duct that Carrie’s secretion to body surface/body cavity e.g. salivary glands Endocrine glands: secrete into extracellular fluid that surrounds cells that make up gland, passes into capillaries to be transported through bloodstream (ductless glands) |
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Endocrine system - hormones: role |
They change the functioning of cells by changing the type, activity or quantities of proteins produced Change activity or concentration of enzymes Activate gene cells so particular enzyme/protein is produced Triggers cascading effect (enzyme amplification) Change structure of enzyme (turns off/on) Change rate of production of enzyme/protein by changing rate of transcription/translation |
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Endocrine system - hormones: defintion |
Hormones can be proteins, amines or steroids Transported in blood to cells/ groups of cells (target cells/target organs) They are specific (lock + key) Saturation can occur (all receptors used up) |
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Endocrine system hormones: types - protein and amine hormones |
Water soluble Attach/bind to receptors on surface of cell membrane of target cells Hormone + receptor = hormone-receptor complex - causes secondary message to diffuse through cell and activate certain enzymes within cytoplasm Fast acting hormones (sec/min) e.g. insulin bonds to receptor = increase in glucose absorption |
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Endocrine system Hormones: types - steroid hormones |
Enter target cell - combine to receptor protein in cytoplasm of cell Lipid soluble (diffuse through cell membrane easily) Receptors found in mitochondria, nucleus or other organelles Hormone-receptor complex enters nucleus to activate genes controlling formation of particular protein (regulates gene expression) Slower acting hormone (hours/days) |
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Endocrine system - hormones: enzyme amplification |
One hormone molecule causes activation of thousands of molecules Hormone triggers cascading effect where number of reacting molecules involves increases by each step along metabolic pathway Small stimulus produces large effect |
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Endocrine system - hormones: hormone clearance |
Once produced required effect it needs to be turned off Breaking down hormone molecule in target cells but mostly in liver + kidney Degraded hormones secreted through bile or urine |
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Endocrine system - hormones: factors |
Regulates by negative feedback system (secretion of hormone is opposite to original stimulus) Factors from hypothalamus regulate function of pituitary gland - releasing factor: stimulates release of hormones Inhibiting factor: slow down release of hormone |
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Endocrine system - hypothalamus |
Controls release of hormones |
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Endocrine system - pituitary gland |
Found under hypothalamus and joined by stalk called infundibulum Two lobes: anterior lobe + posterior lobe |
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Endocrine system - pituitary gland: anterior lobe |
Connected to hypothalamus by network of blood vessels Produces its own hormones Release of hormones controlled by hypothalamus through chemical stimulation Hypothalamus secretes releasing/inhibiting factors into blood which travel down infundibulum to anterior lobe Factors increase/decrease secretion of its hormones |
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Endocrine system - pituitary gland: posterior lobe |
Connected by nerve fibres that come from nerve bodies in hypothalamus Releases hormones that were produced in nerve cell bodies of hypothalamus Hormones travel down axons of nerve cells through infundibulum from hypothalamus Stored in posterior lobe until needed Release is triggered by nerve impulse initiated by hypothalamus |
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Endocrine system - pineal gland |
Deep inside of brain Secrets hormone called melatonin which is involved in regulation of sleep patterns Production of melatonin is stimulated by darkness and inhibited by light |
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Endocrine system - thyroid gland |
Located in neck (just below larynx) Secrets - thyroxine (T4) and triiodothyronine (T3): increase metabolic rate, oxygen consumption and heat production Calcitonin: released when concentration of calcium in blood increases, reduce reabsorption of calcium by kidneys + breakdown of bone |
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Endocrine system - parathyroid gland |
Located in rear surface of thyroid gland Secrete parathyroid hormone (PTH): increases calcium levels in blood + phosphate excretion in urine |
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Endocrine system - thymus |
Located in chest (above heart + behind sternum) Secrete thymosins: influence maturation of disease-fighting cells called T-lymphocytes |
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Endocrine system - adrenal glands |
Two glands - one above each kidney Inner adrenal medulla and outer adrenal cortex |
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Endocrine system - adrenal glands: adrenal medulla |
Produces adrenaline and noradrenaline Adrenaline (epinephrine): similar effect to sympathetic nervous system, helps prepare body for reaction to life threatening situation (fight or flight) Noradrenaline (norepinephrine): similar effects to adrenaline, in particular increases rate + force of heartbeat |
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Endocrine system - adrenal glands: adrenal cortex |
Over 20 different hormones produced in adrenal cortex known collectively as corticosteroids Aldosterone: act on kidney to reduce amount of sodium and increase amount of potassium urine Cortisol: promotes normal metabolism, helps body to withstand stress and repair damaged tissues |
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Endocrine system - pancreas |
Found below stomach alongside duodenum Exocrine + endocrine gland - exocrine: secretes digestive enzymes into small intestine through pancreatic duct - endocrine: made up of clusters of special cells called islets of Langerhans which secret - insulin: secreted by beta cells of islet if Langerhans, reduces amount of glucose in blood - glucagon: secreted by alpha cells of islet of Langerhans, opposite to insulin, increases blood glucose level + stimulate breakdown of fat in liver and fat storage tissues |
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Endocrine system - gonads |
Tested and ovaries They produce - androgens (e.g. testosterone): male sex hormones, development + maintenance of male sex characteristics, produced by testes - oestrogen + progesterone: female sex hormones, produced by ovaries, maintenance of female sex characteristics, with gonadotropic hormones in pituitary they regulate menstrual cycle and involved in changes that occur during pregnancy |
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Endocrine system - other endocrine tissues |
Not endocrine glands but do secrete hormones - stomach + small intestine: secrete hormones that coordinate exocrine glands of digestive system - Kinsey’s: secrete erythropoietin (EPO), stimulates production of red blood cells by bone marrow - heart: secretes hormone to help reside blood pressure Placenta: secretes number of hormones during pregnancy to maintain pregnancy + stimulate development of foetus + stimulate mothers mammary glands |
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Nervous system - definition |
The communication and control system Made up of central nervous system (CNS) and peripheral nervous system (PNS) CNS: - brain + spinal cord - the control centre PNS: - nerve cells, receptors, muscles and glands - Carrie’s messages to and from CNS |
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Nervous system - nerve cells: definition - nerve - nerve fibres |
Nerve cells (neurons): send nerve impulses around body but only in one direction - various shapes + sizes - all neurons contain a cell body, dendrites and axon Nerve: bundle of fibres held together by connective tissue Nerve fibres: any long extension of cytoplasm of nerve cell |
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Nervous system - nerve cells: structure |
Cell body: contains nucleus and cytoplasm with organelles Dendrites: short extensions off cell body, receives messages and carries them towards cell body Axon: single long extension from cell body, varies in length and Carrie’s nerve impulses away from cell body Myelin sheath: layer of lipid (fatty) material covering axon, provides insulation, protection and speeds up nerve impulses Schwann cells: form myelin sheath (wrap around axon) Neurilemma: outermost cool of Schwann cells Nodes of ranvier: gaps in myelin sheath |
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Nervous system - white vs grey matter |
Grey matter: nerve cell bodies and unmyelinated fibres White matter: myelinated fibres |
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Nervous system - functional types of neurons: sensory |
Afferent/receptor Carry messages from receptors in sense organs or skin towards CNS |
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Nervous system - functional types of neurons: motor |
Efferent/effector Carry messages away from CNS towards muscle and glands |
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Nervous system - functional types of neurons: interneurons |
Relay/connector/association neurons Send messages to or from adjacent neurons Link between sensory and motor neurons Located in CNS |
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Nervous system - structural types of neurons: multipolar |
One axon + multiple dendrites Most common Mostly interneurons and motor neurons |
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Nervous system - structural types of neurons: bipolar |
One axon + one dendrite Both axon and dendrite have many branches at their end Ear, eye and nose are mostly interneurons |
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Nervous system - structural types of neurons: pseudounipolar |
Just one extension, an axon Cell body is to one side of axon Most sensory neurons (carry messages to spinal cord) |
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Nervouse System - nerve impulses: definition |
electrochemical change that travels along nerve fibres change in electric voltage caused by changes in the concentration of ions inside + outside of the cell membrane speed depends on: the diameter of fibre and whether it is myelinated or unmyelinated |
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Nervous system - the action potential: background |
like charges repel while opposites attract when opposite charges are separated an electric force pulls them together (the closer the stronger the force) when positive and negative charges are separated they have the chance to come together to release energy potential can be measured through voltage (volts) |
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Nervous system - Action potential: |
fluid inside/around the cell have negative + positively charged ions extracellular fluid: highconcentrations of Na+and Cl- intracellular fluid: highconcentrations of K+and various negative ions potential difference: the difference between concentrations of positive + negative ions inside + outside of cell |
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Nervous system - Action potential: membrane potential |
membrane potential: potential difference created resting membrane potential: membrane potential (difference) of unstimulated nerve cells (-70mV - potential inside of the membrane is 70mV less than the outside) resting potential of neurons is mainly due to differences in the distributions of Na+and K+ - concentration of Na+ions is greater outsidethe neuron - concentration of K+ions is greater insidethe neuron |
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Nervous system - Action potential: cell membrane |
the cell membrane is - highly permeable to K+ - slightly permeable to Na+ - impermeable to various other large negative ions the tendency for K+ to diffuse out of the cell (makes inside more negatively charged) |
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Nervous System - actional potential: beginning |
maintains potential differences through - sodium-potassium pump: cellactively moves Na+ions out of the cell and K+ions in the cell using Na and K protein pumps (3 Na+ molecules for every 2 K+ molecules) - Cellmembrane is not equally permeable to all ions (negatively charged ions trapped in cell) notenough K+ions inside the cell to counteract the large number of negative |
