A2 OCR human biology key definitions
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| 409130906 | Gene | A length of DNA which codes for the production of a particular polypeptide | 1 | |
| 409130907 | Allele | One of the different forms of a gene which occupy the same locus on homologous chromosomes | 2 | |
| 409130908 | Locus | The position on a chromosome at which a particular gene is found | 3 | |
| 409130909 | Phenotype | A person's observable characteristics, resulting from an interaction between their genotype and environment | 4 | |
| 409130910 | Genotype | The genetic make-up of an organism. It describes all the alleles that the nucleus of a human cell contains | 5 | |
| 409130911 | Homozygous | A genotype in which the two alleles of a gene are identical e.g. AA or aa | 6 | |
| 409130912 | Heterozygous | A genotype in which the two alleles of a gene are different e.g. Aa | 7 | |
| 409130913 | Dominant | A dominant allele always shows its effect on the phenotype | 8 | |
| 409130914 | Recessive | A recessive allele only shows its effect on the phenotype when the dominant allele is absent | 9 | |
| 409130915 | Codominant | Both alleles affect the phenotype in a hetero-zygote | 10 | |
| 409130916 | Autosomes | All the chromosomes except the sec chromosomes (X and Y) | 11 | |
| 409130917 | Gene mutation | An alteration of DNA sequence | 12 | |
| 409130918 | Phenylketonuria (PKU) | Genetic disorder in which the essential digestive enzyme phenylalanine hydroxylase is missing. Can lead to severe brain damage in young children. Recessive gene mutation on chromosome 12 | 13 | |
| 409130919 | Cystic fibrosis (CF) | Inherited disorder of exocrine glands resulting in thick mucous secretions in the respiratory tract that do not drain normally. Recessive gene mutation on chromosome 7 | 14 | |
| 409130920 | Huntington's disease | Genetic disorder that causes progressive deterioration of brain cells. Symptoms do not appear until the age of 30 or so. An autosomal dominant gene mutation on chromosome 4 | 15 | |
| 409130921 | Sickle cell anaemia | A severe, chronic blood disease that is hereditary in origin. The abnormal gene produces a crescent shaped red blood cell, which causes the hemoglobin to crystallize within the cell and form painful blood clots and many other medical complications. | 16 | |
| 409130922 | ABO blood groups | Genetically determined classes of human blood that are based on the presence or absence of carbohydrates A and B on the surface of red blood cells; phenotypes, also called blood types, are A, B, AB, and O | 17 | |
| 409130923 | HbA HbA | Normal haemoglobin genotype | 18 | |
| 409130924 | HbA HbS | Half normal haemoglobin, half sickle cell haemoglobin. Codominant genotype | 19 | |
| 409130925 | HbS HbS | Sickle cell anaemia genotype | 20 | |
| 409130926 | Malaria | A disease caused by mosquitoes implanting parasites in the blood | 21 | |
| 409130927 | Heterozygous advantage | Heterozygous alleles have greater selective advantage than either homozygous condition | 22 | |
| 409130928 | Sex linkage | An association between genes in sex chromosomes that makes some characteristics appear more frequently in one sex than in the other | 23 | |
| 409130929 | Haemophilia | Genetic disease affecting the ability of the blood to clot. Sex-linked recessive disease on the X chromosome | 24 | |
| 409130930 | Factor VIII | A coagulation factor whose absence is associated with haemophilia | 25 | |
| 409130931 | Erythrocytes | Red blood cells | 26 | |
| 409130932 | Pedigree diagram | A family tree chart which shows all known phenotypes for the trait/s in question | 27 | |
| 409130933 | Autosomal linkage | A pair of genes that are linked on the same chromosome. The smaller the distance between two loci, increases the chance that alleles will inherit together | 28 | |
| 409130934 | Chiasma | A point of overlap of paired chromatids at which fusion and exchange of genetic material occurs during prophase I of meiosis | 29 | |
| 409130935 | Crossovers | The exchange of genetic material between two paired chromosomes during meiosis | 30 | |
| 409130936 | Crossover frequency | [(Number of recombinant individuals produced) / (Total number of offspring)] x 100 | 31 | |
| 409130937 | Recombinants | Offspring whose phenotype differs from that of the parents; also called recombinant types | 32 | |
| 409130938 | Non-disjunction | Meiosis in which there is a failure of paired homologous chromosomes to separate which results in an abnormal number of chromosomes in the daughter cells | 33 | |
| 409130939 | Translocation | The movement of a segment of DNA from one chromosome to another, which results in a change in the position of the segment | 34 | |
| 409130940 | Turner's syndrome | XO; Females with only one X sex chromosome | 35 | |
| 409130941 | Klinefelter's syndrome | XXY; A chromosomal trisomy in which males have an extra X chromosome; affected individuals typically have reduced fertility | 36 | |
| 409130942 | Down's syndrome | Mental retardation associated with an extra copy of chromosome 21 | 37 | |
| 409130943 | Trisomy | Chromosomal abnormality in which there is one more than the normal number of chromosomes in a cell | 38 | |
| 409130944 | Karyotype | A picture of all the chromosomes in a cell arranged in pairs | 39 | |
| 409130945 | Restriction enzymes | Enzymes that cut DNA at a specific sequence of nucleotides | 40 | |
| 409130946 | Blunt ends | Rragment ends of a DNA molecule that are fully base paired, resulting from cleavage by a restriction enzyme | 41 | |
| 409130947 | Sticky ends | Single stranded ends of DNA left after cutting with enzymes | 42 | |
| 409130948 | Recombinant DNA | Genetically engineered DNA made by recombining fragments of DNA from different organisms | 43 | |
| 409130949 | Anneal | The pairing of complementary strands of DNA | 44 | |
| 409130950 | DNA ligase | A linking enzyme essential for DNA replication | 45 | |
| 409130951 | Intron | Sequence of a eukaryotic gene's DNA that is not translated into a protein | 46 | |
| 409130952 | Exon | Sequence of a gene's DNA that transcribes into protein structures | 47 | |
| 409130953 | Palindromic | Reading the same backwards and forwards | 48 | |
| 409130954 | Gel electrophoresis | Procedure used to separate and analyze DNA fragments by placing a mixture of DNA fragments at one end of a porous gel and applying an electrical voltage to the gel | 49 | |
| 409130955 | Polymerase chain reaction | A method of producing thousands of copies of DNA segment using the enzyme DNA polymerase | 50 | |
| 409130956 | DNA profiling | The analysis of DNA fragments to see who they come from; compares genetic markers from noncoding regions that show variation between individuals | 51 | |
| 409130957 | Minisatellites | Highly repetitive gene sequences that don't code for polypeptides, several thousand sequential copies at many points in the genome | 52 | |
| 409130958 | Primers | Artificially made pieces of single-stranded DNA that are 20 to 30 nucleotides long that must be present for DNA polymerase to initiate replication | 53 | |
| 409160106 | Vector | Used to transport DNA into the host cell | 54 | |
| 409160107 | Plasmid | A small cellular inclusion consisting of a ring of DNA that is not in a chromosome but is capable of autonomous replication | 55 | |
| 409160108 | Recombinant DNA | Genetically engineered DNA made by recombining fragments of DNA from different organisms | 56 | |
| 409160109 | Gene therapy | The insertion of working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder | 57 | |
| 409160110 | Augmentation | Adding a gene (copy of a functional allele) | 58 | |
| 409160111 | Germ cells (gene therapy) | Gene therapy using cells which give rise to eggs or sperm | 59 | |
| 409160112 | Somatic cells (gene therapy) | Gene therapy using non-reproductive cells | 60 | |
| 409160113 | Human Genome Project | An international collaborative effort to map and sequence the DNA of the entire human genome | 61 | |
| 409160114 | Pedigree analysis | The formal study of the pattern of a trait in a pedigree to determine such properties as its mode of inheritance, age of onset, and variability in phenotype | 62 | |
| 409160115 | Genetic counselling | A communication process designed to help couples assess their chances of giving birth to a baby with a hereditary disorder and choose the best course of action in view of risks and family goals | 63 | |
| 409160116 | Transplant surgery | Replaces a malfunctioning body part, tissue, or organ | 64 | |
| 409160117 | HLA antigens | Antigens the body recognizes as self or non-self; present on all body cells except the red blood cells; human leucocyte antigen | 65 | |
| 409160118 | Tissue rejection | Rejection of transplanted tissue results because the recipient's immune system recognizes that the transplanted tissue is not "self" | 66 | |
| 409160119 | Haplotype | Each set of HLA antigens; every person inherits one from each parent | 67 | |
| 409160120 | Xenotransplantation | A surgical procedure in which tissue or whole organs are transfered from one species to another species | 68 | |
| 409160121 | Cadavers | A dead body | 69 | |
| 409160122 | Stem cells | Unspecialised cells that retain the ability to become a wide variety of specialized cells | 70 | |
| 409160123 | Pluripotent | Stem cells with the potential to differentiate into most any type of cell | 71 | |
| 409160124 | Blastocysts | An early embryonic state which embryonic stem cells are derived from | 72 | |
| 409160125 | Compatibility | The ability to accept transplanted tissue | 73 | |
| 409160126 | Major histocompatibility complex (MHC) | The area of chromosome 6 where the loci of the genes for HLA antigens are situated | 74 | |
| 409198003 | Nervous system | The sensory and control apparatus consisting of a network of nerve cells | 75 | |
| 409198004 | Central nervous system | The portion of the vertebrate nervous system consisting of the brain and spinal cord | 76 | |
| 409198005 | Peripheral nervous system | The section of the nervous system lying outside the brain and spinal cord | 77 | |
| 409198006 | Sclera | A tough, white outer layer; protects structures within the eye and maintains the shape of the eye | 78 | |
| 409198007 | Choroid layer | Richly supplied with blood vessels; inner part made up of cells containing the dark pigment, melanin; absorbs light and prevents it from being reflected inside the eye | 79 | |
| 409198008 | Retina | Innermost layer of the eye; contains the receptor cells (rods and cones); receptor cells receive the light stimulus and convert light into nerve impulses | 80 | |
| 409198009 | Fovea | Part of the retina where cones are concentrated; area of maximum visual acuity | 81 | |
| 409198010 | Conjunctiva | Thin layer at the front of the eye; protects the surface of the eye; kept moist by fluid secreted by tear ducts | 82 | |
| 409198011 | Cornea | Continuous with the sclera; refracts light rays entering the eye so focusing light rays onto the retina | 83 | |
| 409198012 | Iris | Contains circular and radial muscles and pigmented cells; helps to control the amount of light passing into the eye | 84 | |
| 409198013 | Pupil | Circular space (hole) in the centre of iris; size altered by the contraction and relaxation of the iris muscles | 85 | |
| 409198014 | Ciliary body | Contains ciliary muscles; helps to control the shape (diameter) of the lens | 86 | |
| 409231438 | Lens | Made up of stacks of long, narrow, transparent cells; about 4 mm thick and biconvex; focuses rays of light onto the retina | 87 | |
| 409231439 | Suspensory ligaments | Ligaments that run between the lens and the ciliary body; holds the lens in place; accommodation | 88 | |
| 409231440 | Vitreous humour | A gelatinous fluid found behind the lens; maintains the shape of the eye | 89 | |
| 409231441 | Aqueous humour | A watery liquid found in front of the lens; maintains the shape of the front of the eye | 90 | |
| 409247676 | Optic nerve | Bundle of nerve fibres; carries action potentials to the brain | 91 | |
| 409247677 | Rods | Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond | 92 | |
| 409247678 | Cones | Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. They detect fine detail and give rise to colour sensations | 93 | |
| 409247679 | Bipolar cells | Specialised cells which connect rods and cones to the ganglion cells of the optic nerve | 94 | |
| 409247680 | Ganglion cells | The specialised cells which lie behind the bipolar cells whose axons form the optic nerve which takes the information to the brain | 95 | |
| 409247681 | Blind spot | The point at which the optic nerve leaves the eye, where no receptor cells are located | 96 | |
| 409247682 | Action potential | A neural impulse; a brief electrical charge that travels down an axon; generated by the movement of positively charged atoms in and out of channels in the axon's membrane | 97 | |
| 409247683 | Resting potential | The potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse; -40mV in rod cells | 98 | |
| 409247684 | Rhodopsin | A visual pigment consisting of retinal and opsin. When it absorbs light, the retinal changes shape and dissociates from the opsin, after which it is converted back to its original form | 99 | |
| 409247685 | Bleaching | The change in the shape of the retinal molecule and the consequent change in shape of the opsin protein | 100 | |
| 409247686 | Visual acuity | Sharpness of vision | 101 | |
| 409247687 | Snellen chart | Display consisting of a printed card with letters and numbers in lines of decreasing size to test eye sight | 102 | |
| 409247688 | Ishihara test | Test for colour blindness | 103 | |
| 409247689 | Brain | The part of the central nervous system that is located in the skull and controls most functions in the body | 104 | |
| 409247690 | Cranium | The part of the skull that encloses the brain | 105 | |
| 409247691 | Meninges | A membrane (one of 3) that envelops the brain and spinal cord | 106 | |
| 409247692 | Blood-brain barrier | Blood vessels (capillaries) that selectively let certain substances enter the brain tissue and keep other substances out | 107 | |
| 409247693 | Cerebral cortex | The layer of unmyelinated neurons (the gray matter) forming the cortex of the cerebrum | 108 | |
| 409247694 | Cerebrum | Anterior portion of the brain consisting of two hemispheres | 109 | |
| 409247695 | Cerebellum | The "little brain" attached to the rear of the brain stem; its functions include processing sensory input and coordinating movement output and balance | 110 | |
| 409247696 | Sympathetic branch | The division of the autonomic nervous system that mobilizes the organism for physical exertion | 111 | |
| 409247697 | Parasympathetic branch | The division of the autonomic nervous system that restores the body's normal resting state and conserves energy | 112 | |
| 409247698 | Frontal lobe | The lobe at the front of the brain associated with movement, speech, and impulsive behavior | 113 | |
| 409247699 | Parietal lobe | Portion of the brain behind the frontal lobe; responsible for sensations such as pain, temperature, and touch | 114 | |
| 409247700 | Occipital lobe | Portion of the brain posterior to the parietal and temporal lobes; responsible for vision | 115 | |
| 409247701 | Temporal lobe | The portion of the cerebral cortex that is just above the ears and that is involved in hearing, language processing, and memory | 116 | |
| 409247702 | Cerebellum | Involved in coordinating your muscles to allow precise movements and control of balance and posture | 117 | |
| 409247703 | Medulla oblongata | Lies beneath the cerebellum; forms the link between the brain and the spinal cord | 118 | |
| 409247704 | Hypothalmus | Brain structure that acts as a control center for recognition and analysis of hunger, thirst, fatigue, anger and body temperature | 119 | |
| 409247705 | Motor neurone | Type of neurone that caries messages from the brain and spinal cord to an effector | 120 | |
| 409247706 | Sensory neurone | Neurones conveying signals from a receptor to the CNS | 121 | |
| 409247707 | Relay neurone | A neurone in the CNS which passes impulses from one neurone to another | 122 | |
| 409247708 | Axon | Long nerve fibre that conducts away from the cell body of the neuron | 123 | |
| 409247709 | Dendron | Carries action potentials towards the cell body | 124 | |
| 409247710 | Dendrites | Very short processes that carry nerve impulses towards the cell body | 125 | |
| 409247711 | Schwann cells | Part of the neuron that produces the myelin sheath; functions in repair and regeneration of damaged nerves; wrap around the axon; aid the myelin in insulation | 126 | |
| 409247712 | Myelin sheath | A layer of myelin encasing (and insulating) the axons of medullated nerve fibers | 127 | |
| 409247713 | Nodes of Ranvier | Small gaps in the myelin sheath of medullated axons | 128 | |
| 409247714 | Reflex arc | A relatively direct connection between a sensory neurone and a motor neurone that allows an extremely rapid response to a stimulus, often without conscious brain involvement | 129 | |
| 409247715 | Receptor | Specialised cell that monitors conditions in the body or external environment; has a characteristic range of sensitivity | 130 | |
| 409247716 | Effector | A nerve fibre that terminates on a muscle or gland and stimulates contraction or secretion | 131 | |
| 409488184 | Polarised | Membrane with a potential difference across it | 132 | |
| 409488185 | Resting potential | The potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse; -70 mV in neurones | 133 | |
| 409488186 | Sodium/potassium pump | A carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell | 134 | |
| 409488187 | Potential difference | A measure of the charge difference across the cell membrane | 135 | |
| 409488188 | Depolarised | When the axon undergoes an action potential, usually +40 mV | 136 | |
| 409488189 | Hyperpolarised | The condition of a membrane that is more highly polarised than the usual resting state. The resting potential is lower than usual; -90 mV | 137 | |
| 409488190 | All or nothing law | The principle that either a neuron is sufficiently stimulated and an action potential occurs or a neuron is not sufficiently stimulated and an action potential does not occur | 138 | |
| 409488191 | Refractory period | The time after a neuron fires or a muscle fibre contracts during which a stimulus will not evoke a response | 139 | |
| 409488192 | Saltatory conduction | Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane | 140 | |
| 409488193 | Synapse | The junction between two neurons (axon-to-dendrite) or between a neuron and a muscle | 141 | |
| 409488194 | Synaptic cleft | Synaptic gap or synaptic space; tiny gap between the terminal of one neuron and the dendrites of another neuron (almost never touch); location of the transfer of an impulse from one neuron to the next | 142 | |
| 409488195 | Neurotransmitter | A chemical used by a neuron to transmit an impulse across a synapse to another cell | 143 | |
| 409488196 | Cholinergic synapse | A junction between neurons that uses acetylcholine as the neurotransmitter | 144 | |
| 409488197 | Synaptic bulb | Where neurotransmitters are made; contain mitochondria, endoplasmic reticulum and synaptic vesicles containing the neurotrasnsmitter | 145 | |
| 409488198 | Postsynaptic membrane | Effector cell or neurone that is the receiver of the neurotransmitter (part of the synapse) | 146 | |
| 409488199 | Synaptic cleft | Space between two connecting neurons where neurotransmitters are released | 147 | |
| 409488200 | Calcium ion channels | Pathway in the plasma membrane through which calcium ions enter and leave | 148 | |
| 409488201 | Synaptic vesicles | Tiny sacs in a terminal button that release chemicals into the synapse | 149 | |
| 409488202 | Acetylcholinesterase | An enzyme that breaks down the neurotransmitter acetylcholine | 150 | |
| 409488203 | Traumatic brain injury (TBI) | A blow to the head or a penetrating head injury that damages the brain | 151 | |
| 409488204 | CT scan | A series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body | 152 | |
| 409488205 | MRI scan | Uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue | 153 | |
| 409488206 | Nerve conduction velocity test | An electrical shock of peripheral nerves to record time of conduction; used to diagnose various peripheral nervous system diseases | 154 | |
| 409488207 | Glial cell | One of the cells that provide structural support for neurons | 155 | |
| 409488208 | Stroke | Occurs when there is an interruption of blood supply to a region of the brain, depriving nerve cells in the affected area of oxygen and nutrients | 156 | |
| 410790205 | Drug | Any chemical that affects the way your body functions, and how you think and feel | 157 | |
| 410790206 | Parkinson's disease | A progressive disease that destroys brain cells and is identified by muscular tremors, slowing of movement, and partial facial paralysis | 158 | |
| 410790207 | Dopamine | Neurotransmitter that influences voluntary movement, attention, alertness; lack of dopamine linked with Parkinson's disease | 159 | |
| 410790208 | Diamorphine (heroin) | Can be used to relieve severe pain; chemical derivative of morphine | 160 | |
| 410790209 | Endorphins | Neurotransmitters that give one a feeling of well-being, euphoria or eliminate pain | 161 | |
| 410790210 | Opioid | A chemical, such as opium, heroin, and other molecules with related structures that reduce pain and induce feelings of euphoria | 162 | |
| 410790211 | Cannabis | Substance that causes feelings of well-being, perceptual distortions, and paranoid thinking | 163 | |
| 410790212 | Physical dependence | A physiological need for a drug, marked by unpleasant withdrawal symptoms when the drug is discontinued | 164 | |
| 410790213 | Psychological dependence | The condition that exists when a person must continue to take a drug in order to satisfy intense mental and emotional craving for the drug | 165 | |
| 410836714 | Homeostasis | Metabolic equilibrium actively maintained by several complex biological mechanisms that operate via the autonomic nervous system to offset disrupting changes | 166 | |
| 410836715 | Vasodilation | Dilation of blood vessels (especially the arteries) | 167 | |
| 410836716 | Thyroxine | Hormone produced by the thyroid glands to regulate metabolism by controlling the rate of oxidation in cells; increases metabolic rate | 168 | |
| 410836717 | Vasoconstriction | Decrease in the diameter of blood vessels | 169 | |
| 410836718 | Hypothermia | Subnormal body temperature; <35C | 170 | |
| 410836719 | Hyperthermia | Abnormally high body temperature | 171 | |
| 410836720 | Islets of Langerhans | Cell clusters in the pancreas that form the endocrine part of that organ | 172 | |
| 410836721 | Pancreas | A large elongated exocrine and endocrine gland located behind the stomach | 173 | |
| 410836722 | Endocrine | Any of the glands of the endocrine system that secrete hormones directly into the bloodstream | 174 | |
| 410836723 | Glucagon | A hormone secreted by alpha cells in the islets of Langerhans; causes increase blood glucose concentration | 175 | |
| 410836724 | Insulin | A hormone secreted by beta cells in the islets of Langerhans; causes a decrease in blood glucose concentration | 176 | |
| 410836725 | Glycogenesis | The conversion of glucose to glycogen when the glucose in the blood exceeds the demand | 177 | |
| 410836726 | Glyconeogenesis | Process of producing glucose from fat and protein | 178 | |
| 410836727 | Type 1 diabetes | Insulin dependent; body is unable to produce insulin because the beta cells are destroyed by own immune system | 179 | |
| 410836728 | Type 2 diabetes | Insulin independent; the body target cells lose their responsiveness to insulin; can be caused by obesity | 180 | |
| 411251142 | Excretion | Removal of waste products of metabolism from the body | 181 | |
| 411251143 | Metabolism | Chemical processes occurring within a living cell or organism that are necessary for the maintenance of life | 182 | |
| 411251144 | Deamination | The removal of an amino group from an amino acid; breaks off NH2 from amino acids turning it into ammonia | 183 | |
| 411251145 | Cortex (kidney) | Outer region of the kidney | 184 | |
| 411251146 | Medulla (kidney) | The inner part of the kidney | 185 | |
| 411251147 | Pelvis (kidney) | The funnel shaped cavity that receives the urine in the kidney | 186 | |
| 411251148 | Nephron | Functional unit of the kidney | 187 | |
| 411251149 | Bowman's capsule (renal capsule) | Cup-shaped end of renal tubule containing the glomerulus | 188 | |
| 411251150 | Glomerulus | Small network of capillaries encased in the upper end of a nephron; where the filtration of blood takes place | 189 | |
| 411251151 | Proximal convoluted tubule | First section of the renal tubule that the blood flows through; reabsorption of water, ions, and all organic nutrients | 190 | |
| 411251152 | Loop of Henle | Section of the nephron tubule that conserves water and minimizes the volume of urine | 191 | |
| 411251153 | Distal convoluted tubule | Between the loop of Henle and the collecting duct; selective reabsorption and secretion occur here, most notably to regulate reabsorption of water and sodium | 192 | |
| 411251154 | Collecting duct | The portion of the nephron where water reabsorption is regulated via antidiuretic hormone (ADH); several nephrons empty into each collecting duct, and this is the final region through which urine must pass on its way to the ureter | 193 | |
| 411251155 | Ultrafiltration | The process by which fluid and small molecules are filtered out of the blood in the glomerulus | 194 | |
| 411251156 | Selective reabsorption | Process in the kidney that puts useful substances (water, glucose, amino acids) back into the blood | 195 | |
| 411251157 | Afferent arteriole | The small artery that carries blood toward the capillaries of the glomerulus | 196 | |
| 411251158 | Efferent arteriole | The small artery that carries blood away from the capillaries of the glomerulus | 197 | |
| 411251159 | Basement membrane | Acts as a molecular filter allowing proteins with a molecular mass less than 69000 through | 198 | |
| 411251160 | Podocytes | A cell with branching tentacle-shaped extensions that constitutes the barrier through which blood is filtered in the glomerulus of the kidney | 199 | |
| 411251161 | Microvilli | Fingerlike extensions of the plasma membrane | 200 | |
| 411251162 | Osmoreceptors | Sensory receptors in the hypothalamus that detect changes in the osmotic pressure of the blood and surrounding extracellular fluids | 201 | |
| 411251163 | Antidiuretic hormone (ADH) | Hormone released from the hypothalamus; inhibits urine production; causes kidneys to reabsorb water; increases blood pressure | 202 | |
| 411251164 | Posterior pituitary gland | ADH passes along the axons of the neurosensory cells which end in the __________ from where ADH is released into the blood plasma | 203 | |
| 411251165 | Cyclic AMP (cAMP) | Leads to the insertion of aquaporins into the collecting duct cell membrane, where they open, making the membrane more permeable to water | 204 | |
| 411251166 | Aquaporins | Water channel proteins that allow water to pass through them | 205 |
