BIOLOGY 3201 TERMINOLOGY NERVOUS/ENDOCRINE SYSTEMS 1. Dendrite - hairlike receptors on the ends of neurons. 2. Neuron - Basic unit of the nervous system. 3. Soma - Cell body. 4. Axon - long extension leading away from the soma. 5. Myelin Sheath - fatty layer of tissue that surrounds an axon. 6. Nodes of Ranvier - gaps between myelin on the axon. 7. Schwaan cell - cells that help to make up the myelin sheath. 8. Synapse - gap between neurons 9. Sensory neuron - neuron that receives incoming stimuli 10. Interneuron - neuron that passes impulses from a sensory neuron to a motor neuron. 11. Motor neuron - neuron connected to a muscle (effector) that carries out an impulse. 12. Action potential - firing of a neuron. Also known as depolarization 13. Threshold level - minimum stimulus required to cause a response. 14. All or none response - neuron will completely fire or not at all. 15. Acetylcholine excitatory neurotransmitter found in synapses of neurons. Stimulates skeletal muscle and inhibits cardiac muscle. 16. Adrenalin/Noradrenalin - see above 17. Cerebral cortex - outer region of the brain (cerebrum); involved in thought and reasoning.
18. Medulla Oblongata - part of brain stem. Regulates many involuntary activities including increasing heart rate. 19. Vagus nerve - found at base of brain. Decreases heart rate. 20. Cerebellum - region of the brain that controls motor coordination and balance. 21. Pons - relay centre between the medulla and the cerebellum. 22. Corpus Callosum - band of white matter that connects the two cerebral hemispheres. Relay center between left and right hemispheres. 23. Glial cells - support and nourish neurons in the brain. 24. White matter - nerve tissue that is myelinated. 25. Gray matter - nerve tissue that is unmyelinated. 26. Gyri - folds in the brain 27. Meninges - protective membranes that cover the brain and spinal cord. 28. CNS - Central nervous system. Made up of brain and spinal cord. 29. PNS - Peripheral nervous System. Made up of nerves supplying the brain and spinal cord. 30. Dorsal Root - nerve root that is connected to a sensory neuron in the spinal cord. 31. Ventral root - nerve root that is connected to a motor neuron. 32. ANS - Autonomic nervous system. 33. Sympathetic Nervous System - part of the ANS. Prepares the body for emergencies. 34. Parasympathetic nervous system - part of the ANS. Brings the body back to normal after an emergency. 35. Cholinesterase - enzyme that destroys acetylcholine in a synapse. 36. Sodium/Potassium pump - pump in a neuron that actively removes ions after an action potential. Removes 3 Na + ions for every 2 K + ions it brings in.
37. Saltatory conduction - the process of action potentials jumping the gaps in neurons thereby speeding them up. 38. Parietal lobe - region of the brain responsible for motor functions and senses. 39. Frontal lobe - region of the brain that is involved in thought and reasoning. 40. Occipital lobe - region of the brain responsible for sight. 41. Temporal lobe - region of the brain responsible for hearing 42. Optic chiasma - junction where the two optic nerves cross. 43. Ganglia - a mass of nerve cells. 44. Paraplegic - paralysis of two limbs. 45 Quadriplegic - paralysis of 4 limbs. 46. Resting potential - normal state that an axon is at. Normally - 70 mvolts. Outside of neuron is + while inside is - 47. Depolarization - process of reversing the normal charge in an axon. Outside becomes while inside becomes +. 48. Repolarization - process of restoring the original arrangement of ions in an axon. Done with the help of the sodium/potassium pump. 49. Summation - the process of needing more than one axon firing to meet the threshold level of a third axon. 50. Refractory period - period when no other action potentials can occur. The axon is restoring its original arrangement of ions. 51. Reflex arc - the path a reflex takes. 52. Reflex act - the action carried out as a result of a reflex. 53. Patella reflex - reflex of the knee. 54. Babinski reflex - reflex of the bottom of the foot. 55. Pupillary reflex - reflex of the pupil.
56. Endorphins - group of natural pain killers produced by the body to reduce pain. 57. Cornea - thin layer of transparent tissue on the front of the eye. Helps to focus light onto the lens. 58. Lens - hard clear structure in the eye that focuses light onto the retina. 59. Conjuctiva - layer of protective tissue on the inside of the eyelid. Serves to protect the front of the eye. 60. Aqueous humour - clear fluid in the front chamber of the eye. 61. Suspensory ligament - ligament that is attached to the lens. 62. Ciliary muscle - muscle attached to the suspensory ligament. Functions in changing the shape of the lens for focusing. 63. Vitreous humour - clear fluid in the posterior portion of the eye. 64. Retina - layer of tissue at the back of the eye. Where light is focused. Contains rods and cones. 65. Sclera - outer layer of the eye. Serves to protect the eye. 66. Choroid layer - middle layer of tissue in the eye. Serves to prevent scattering of light in the eye. 67. Fovea centralis - region at the back of the eye where there is a large concentration of rods and cones. 68. Blind Spot - region where the optic nerve enters the eye. No rods or cones here so no vision. 69. Optic nerve - sensory nerve that carries impulses to the brain. 70. Iris - the colouring tissue of the eye. Serves to control the amount of light entering the eye. 71. Pupil - the opening into the eye. Where light passes through to the lens. 72. Rods - photosensitive cells in the retina that detect low levels of light and are mainly used at night.
73. Cones - photosensitive cells in the retina that are used for detecting colour and bright light. 74. Afterimages - images left on the retina after the light is removed. 75. Positive afterimage - an afterimage that appears to be the same colour as the original object. 76. Negative after image - afterimage that appears in black and white. 77. Accommodation - the process of the lens changing shape to account for viewing near and far objects. 78. Myopia - near sightedness. Caused when the eye is too long. 79. Hyperopia - far sightedness. Caused when the eye is too long. 80. Rhodopsin - pigment needed in order for the cones and rods to detect light. 81. Glaucoma - vision problem where there is too much pressure in the eye. Caused by irregular draining of vitreous and aqueous humours. 82. Astigmatism - vision defect because of irregular curvature of the lens or cornea. 83. Stereoscopic vision -vision as a result of two separate images being made into one by the brain. 85. Pinna - outer fleshy part of the ear. Directs sound waves to the auditory canal. 86. Auditory canal - long canal that leads from the pinna to the tympanic membrane. Serves to amplify sound waves. 87. Tympanic membrane - thin membrane found at the end of the auditory canal. Changes sound energy into mechanical energy. 88. Ossicles - group of three small bones in the ear that conduct mechanical waves in the ears. Called the Hammer - Malleus, Anvil - Incus, and Stirrup - Stapes. 89. Eustachian tube - tube that leads from the middle ear to the back of the throat. Serves to equalize pressure in the ear. 90. Oval window - small layer of tissue that covers the opening of the cochlea. Receives sound waves from the stapes.
91. Cochlea - snail-shaped structure in the ear that is filled with fluid and conducts sound. 92. Round window - flap of tissue at the end of the cochlea that serves to dampen vibrations within the cochlea. 93. Organ of Corti - thin layer of tissue that has hair cells that are responsible for detecting sound in the cochlea. The basilar membrane moves when the cochlear fluid moves. 94. Perilymph - fluid found in the cochlea and the semicircular canals. 95. Scali vestibuli - one of the regions in the cochlea. 96. Scali tympani - one region in the cochlea. 97. Auditory nerve - sensory nerve that transmits electrical impulses to the brain. 98. Semicircular canals - set of three fluid filled canals that control dynamic balance. 99. Otoliths - small bones in the inner ear that detect the position of the head. Static balance. 100. Saccule/Utricle - small fluid filled sacs that contain otoliths in the inner ear. 101. Endocrine system - system where hormones are dumped into the blood to help maintain homeostasis. 102. Paracrine hormone - hormone that affects the cell next to where it was made. 103. Endocrine hormone - hormone that affects a cell away from the cell where it was made. 104. Autocrine hormone - hormone that affects the cell where it was made. 105. Exocrine gland - a gland that has duct. Ex : salivary gland 106. Endocrine gland - a ductless gland that dumps hormones directly into the blood. 107. The endocrine glands - Pituitary Thyroid Parathyroid Pineal
Thymus Adrenal Testicles Ovaries Pancreas 108. Hormone - chemical that is released into the blood to cause cells to carry out an action. 109. Steroid hormone - Hormone that is made up of fats such as cholesterol. 110. Non-Steorid hormone - hormone made from a protein. 111. Pituitary gland - the master gland. Found at the base of the brain. Has two parts. Posterior and Anterior. 112. Anterior Pituitary - Stores hormones created in the hypothalamus. 113. Posterior Pituitary - stores hormones created there. 114. Hypothalamus - found in the brain. Controls the autonomic nervous system and the internal organs. Monitors the blood for hormone levels and causes the pituitary to react. 115. FSH - Follicle stimulating hormone. Found in the anterior pituitary. Causes immature follicles to mature in females. Causes the testicles to create sperm. 116. LH - Luteinizing Hormone - found in the anterior pituitary. Causes the testicles to release testosterone. Causes ovulation in females. 117. GH - Growth Hormone - Found in Anterior pituitary. Causes growth of cells. 118. ICSH - Interstitial Cell Stimulating Hormone - Causes sperm to mature in the testicles of males. 119. Prolactin - stimulates milk production in the female. 120. TSH - Thyroid Stimulating Hormone - causes the thyroid to release thyroxin. 121. ACTH - Adrenocorticotrophic Hormone - causes the adrenal gland to release hormones. 122. Oxytocin - found in posterior pituitary. Causes the uterus to contract and helps with the release of milk in females.
123. ADH - Antidiuretic Hormone(Vasopressin) - Found in the Posterior pituitary. Causes the kidneys to reabsorb water from the collecting tubules. 124. Thyroxin - found in thyroid. Increases the body s metabolism. Needs iodine to work properly. 125. Calcitonin - found in thyroid - lowers calcium levels in the blood by inhibiting calcium release from the bones. 126. Parathyroid Hormone - increase the calcium level in the blood by causing the bones to release calcium. 127. Melatonin Hormone released by pineal gland. Associated with sleeping.. 128. Insulin - found in the pancreas. Lowers blood sugar levels. 129. Glucagon - increases sugar level by causing the liver to convert glycogen into glucose. 130. Adrenaline Fight or Flight hormone. Increases blood sugar. Constricts blood vessels. 131. Noradrenaline - increases heart rate and causes muscles to contract. 132. Aldosterone - hormone that regulates water level by controlling salt levels in the blood. Helps regulate blood pressure. 133. Estrogen - causes the initial buildup of the uterus. Causes secondary sex characteristics to develop in females. 134. Progesterone - released by the corpus luteum. Maintains the uterine lining during pregnancy. 136. Testosterone - causes sperm to mature in males. responsible for secondary sex characteristics in males. 137. Gonadotropins - hormones that are produced or affect the gonads of males and females. 138. Homeostasis - the maintaining of a constant internal environment by reacting to stimuli. Reactions can be carried out by any system in the body.