Nervous & Endocrine Systems Biology 30 Diploma Prep % of Diploma Questions

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1 Nervous & Endocrine Systems Biology 30 Diploma Prep 20-25% of Diploma Questions

2 Central Nervous System (CNS) Decision maker Nervous System Nervous System Organizational Tree! Peripheral Nervous System (PNS) Feeds into & out of CNS Brain & Spinal Cord Sensory Pathway Motor Pathway Somatic Pathway (Voluntary) under conscious control Examples? Autonomic Pathway (Involuntary) unconscious control Examples? Sympathetic (Stimulatory) Speeds you up! Excites you! Parasympathetic (Restores to normal) Restores balance! Restores Homeostasis!

3 5 major components Stimulus receptor -highly specific -receive stimuli Sensory Pathway modulator/regulator Motor Pathway effector -carries out the response (muscle or gland) Action

4 Nerves versus Neurons

5 Three Types of Neurons 1. Motor-Carries information from the CNS to the effectors (muscles/glands). Located in the PNS 2. Sensory-Carries information a sensory receptor to the CNS. Located in the PNS 3. Interneuron Connect sensory neurons to motor neurons Connects two or more neurons Found in CNS **Glial Cells nourish the neurons, remove waste and defend against infection. Outnumber neurons 10 to 1.

6 Structures of Neuron Dendrites Pick up impulses from previous neuron and carry to the cell body Cell Body Produces many chemicals needed by the neuron Preforms metabolism Axon Carries impulses from the cell body to the synapse Functions to insulate the axon thus increasing speed of transmission

7 Axon In the CNS,oliogodendrocytesform the fatty white myelin sheath forms around the axon In the PNS, Schwann Cells form the fatty white myelin sheath by wrapingaround the axon. As each Schwann cell wraps around the nerve fiber, its nucleus and cytoplasm are squeezed to the perimeter to form the neurilemma The function of the neurilemmais the regeneration of nerves

8 Myelin Sheath

9 Structures of Neuron Nodes of Ranvier Gaps between the myelin sheath Impulses jump from one node to the next during Saltatory conduction Synapse Junction between the pre-synaptic neuron and the post-synaptic neuron Synaptic knobs contain Vesicles that release the neurotransmitter aceylcholine Mitochondria to produce ATP for neurotransmitter synthesis

10 Synapse

11 Reflex Arc Occurs without brain involvement or conscious thought Involves the spinal cord ONLY and thus the response is quick and involuntary Example: touching a flame Reflex Arc Parthway: Sensory receptor Sensory Neuron Interneuron Motor Neuron Effector

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14 Impulse Transmission (Excitatory) 1. Resting Potential A positive outside and negative inside MUSTbe created across the axon s membrane BEFORE it can transmit an impulse! Created by the sodium-potassium pump that pumps 3 Na + out of the cellfor every 2 K + in (requires ATP) This difference in charge creates a voltage of -70 mv when measured with a voltmeter The axon membrane is described as polarized.

15 Impulse Transmission (Excitatory) 2. Action Potential As the impulse starts moving down the axon, the axon s permeability changes in that Na + starts to moving into the axon to create an axon with a positive inside and negative outside Called a wave of depolarization or depolarized membrane. This occurs ONLY at the nodes of Ranvier as the myelin sheath insulates the axon it encircles

16 Impulse Transmission (Excitatory) 3. Repolarization Na gates close, K gates open K ions diffuse out of the axon making the inside more negative, outside more positive After the impulse passes through the axon, the Na + and K + are on opposite sides of the axon. Thus, the sodium-potassium pump restores the resting membrane potential by pumping 3 Na + out for every 2 K + in Every axon must repolarize BEFORE it can transmit a second impulse!

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18 Threshold Level The minimum amount of an impulse needed to get an action potential (response) Each neuron has a different threshold level If the impulse exceeds the threshold the response is the SAME.called the ALL or NONE RESPONSE Stimulus Muscle Contraction 1 mv -- 2 mv -- 3 mv 5N 4 mv 5N

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20 Synapse Once an impulse reaches the synapse, the Synaptic knob releases acetylcholine Attaches to receptors on the dendrites of the post-synaptic neuron Causes depolarization of the post-synaptic neuron so the impulse continues Acetylcholine is then broken down by cholinesterase (released by the dendrites of the post-synaptic neuron) Repolarization is allowed to occur

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22 Other random bits of information: Stimuli Intensity is detected 2 ways: The more intense the stimulus, the higher the frequency of impulses Each neuron has its own threshold level. The more impulses that reach the brain, the stronger the response. A neuromuscular junction is a synapse between a motor neuron and a muscle cell (works in much the same way) The Refractory period is the time it takes a neuron to repolarize (no other impulses may be passed during that time) Summationoccurs when acetylcholine is needed from 2 or more neurons to cause depolarization of the post-synaptic neuron Hyperpolarizationof an axon inhibits impulses from being transmitted when outside of the axon becomes more positive than normal due to an accumulation of K + leaking outside the axon. As a result, getting enough Na + inside the axon for depolarization is almost impossible. (Na/K pump restores resting potential)

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24 NS Question #2 NS Question #3

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26 NS Question #5 NS Question #6

27 NS Question #7 NS Question #8

28 Autonomic Nervous System (involuntary) Sympathetic Prepares body for stress Effects include: Increased heart rate Increased release of epinephrine Increased breathing rate Increased metabolism Increased blood flow (vessels dilate) Pupils dilate Decreased peristalsis (digestion) Increased conversion of glycogen to glucose Bladder sphincter relaxes Parasympathetic Returns body to normal Effects include: Decreased heart rate Release of epinephrine stops Decreased breathing rate Decreased metabolism Decreased blood flow (vessels constrict) Pupils constrict Increased peristalsis Stores glucose in liver and muscles Bladder sphincter contracts

29 Central Nervous System (CNS) Brain is protected by skull and 3 protective membranes called meninges Cerebrospinal fluid (CSF) circulates between the meninges and the central canal of the spinal cord Function of the CSF is shock absorber and transport of nutrients and wastes Level of brain development makes humans unique

30 Spinal Cord Connects sensory and motor nerves to brain Contains white matter (myelinatedfrom oliogodendrocytes) and grey matter (unmyelinated).will these nerves regenerate??? Why or why not????

31 Brain -Forebrain Contains the following: Cerebrum(2 hemispheres) largest and most highly developed part of the brain. Controls speech, reasoning, memory, personality, stores sensory information and imitates motor activity. Made of 4 lobes: Frontal front of head. Responsibility for personality and higher level cognitive functioning Parietal top of head. Responsible for touch, taste and pressure Occipital back of head. Responsible for vision Temporal near temples. Responsible for hearing and smell

32 Midbrain Contains the following : Cerebral Cortex covers the cerebrum. Made of grey matter and is highly folded to increase the surface area Corpus Callosum allows the two hemispheres to communicate Thalmus below the cerebrum. Coordinates/interprets sensory information Hypothalamus below thalamus. Coordinates endocrine function. Pituitary Gland connected to hypothalamus, hangs like a pendant on a necklace. Links nervous and endocrine systems.

33 Hindbrain Joins with the spinal cord. Contains the following: Cerebellum coordinates muscle movement. Beneath cerebrum. Medulla Oblongata joins spinal cord to cerebellum. Controls all vital functions (Autonomic NS) Pons relay station between medulla and cerebellum Right side of brain controls left side of body and vice versa

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36 NS Question #9

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39 NS Question #12 NS Question #13

40 NS Question #14

41 Senses Sensory receptors pick up information from our environment and send this information to our brain along sensory neurons Sensationoccurs when neural impulses arrive at the cerebrum Each persons unique perception results from how the cerebellum interprets the meaning of the sensory information Sensory adaptation occurs when the receptors have adjusted to changes in the environmental stimuli

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43 Taste and Smell Work together (eg. A cold) Taste sensory receptors are located on the tongue as taste buds Smell sensory receptors are olfactory cells in the nose. Airborne particles cause depolarization of the olfactory cells. They exhibit sensory adaptation.

44 Touch Sensory receptors located all over the body. Many are concentrated in the genitals, fingers, tongue and lips. Sensitive to touch, pressure, pain and high/low temperatures

45 Vision Structure 3 layers 1. Sclera outer layer that supports/protects the inner layers Cornea transparent and bends light towards pupil. Receives oxygen from the gases dissolved in tears (no blood vessels because they would distort vision) Aqueous Humor transparent fluid behind cornea that supplies nutrients to cornea

46 2. Choroid middle layer (dark black color, contains blood vessels) Iris muscle that controls the size of the pupil and thus the amount of light entering the eye Lens behind the iris. Focuses the image on the retina. Ciliary muscles change the shape of the lens. Vitreous Humor jelly like fluid-filled chamber behind the lens. Maintains the shape of the eye

47 3. Retina inner layer. Contains 2 sensory photoreceptors. Rods used when viewing in dim light, concentrated in periphery Cones used for color vision and bright light Fovea Centralis center of the retina and most sensitive. Contains cones ONLY and rods surround on periphery Blind Spot where the optic nerve attaches to retina. Contains NO rods or cones.

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49 Focusing an Image Light enters the eye through the pupil whose size is controlled by the iris Light is bent by the cornea towards the pupil/lens Lens changes its shape as it bends the light onto the retina (inverted image) Rods/cones are the sensory receptor and when hit by light generate a nerve impulse down the optic nerve, through the optic chiasmato the occipital lobe

50 The lens ability to change its shape when viewing near/far objects is called the accomodation reflex Close objects ciliarymuscles contract and htusthe lens thickens. The pupil constricts to focus the image on the retina Far objects ciliarymuscles relax and the lens thins. Pupil dilates to increase the amount of light entering the eye. As we age, protein builds up on the lens and thus is less flexible to accommodate when viewing close objects

51 Vision Defects = STS Glaucoma buildup of aqueous humor and thus the fluid pressure causes blood vesslesto collapse and oxygen and nutrients decrease. Result is neuron death and blindness Cataracts lens/cornea is cloudy and thus light cant pass through. The lens can be replaced Astigmatism abnormal curvature of the lens/cornea Myopia/nearsightedness eyeball is too long and thus image is focused in front of the retina. Corrected with a concave lens Hyperopia/farsightedness the eyeball is too short and thus the image is focused behind the retina. Corrected with a convex lens Colorblindness 1 or more type of cone is missing/defective. Most common is red-green colorblindness and is most common in males as the gene is carried on the X chromosome.

52 Hearing The hear has two functions hearing and balance Structures: 1. Outer ear air filled Pinna Funnels sound vibrations into auditory canal Auditory Canal carries sound waves to the eardrum. Contains wax to trap foreign particles

53 2. Middle Ear Air filled Tympanic membrane/eardrum vibrates and passes sound waves to ossicles Ossicles 3 tiny bones that amplify sound waves. These amplified sound waves are then passed onto the oval window membrane and then the round window membrane Malleus/Hammer Incus/Anvil Stapes/Stirrup Eustachian Tube equalizes air pressure between internal and external ear. Has no function in hearing!

54 3. Inner Ear contains fluid filled structures Vestibule connected to the oval window at the base of the semi-circular canals. Function is balance and head position (static equilibrium) Semicircular canals attached to the vestibule. Function is balance and body position (dynamic equilibrium) Cochlea contain specialized hair cells that convert amplified sound waves vibrations into electrochemical nerve impulses

55 Cochlea Contains the Organ of Corti (actual hearing apparatus) that is composed of hair cells attached to a basilar membrane. When fluid moves due to amplified sound vibrations, hair cells bend due to the movement of the basilar membrane. Cochlea is protected by loud noises in two ways Muscles connected to malleus contract thus restricting its movement as it passes vibrations on Muscles of the ossiclescontract so stapes is moved away from the oval window.

56 Cochlea con t Cochlea detects different pitches when different areas are stimulated STS two types of hearing loss: Nerve Deafness damage to hair cells Conduction Deafness damage to the sound conduction system of the outer/middle ear Nerve pathway = Cochlea Auditory Nerve Temporal Lobe

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59 Balance/Equilibrium Static/Gravitational Equilibrium (head position) contains 2 fluid filled sacs that contain hair receptors. The sacs are the sacculeand utricle. The sacs contain otoliths (tiny stones) so when we move our head, the stones move and bend hairs which stimulate sensory nerves to the brain Dynamic/Rotational Equilibrium (body position) fluid filled semi circular canals. The movement of the fluid causes hair cells to move and therefore initatesnerve impulses to the brain. Motion sickness is the continuous movement of fluid.

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61 Senses #1

62 Senses #2

63 Senses #3

64 Senses #4

65 Senses #5

66 Senses #6 Senses #7

67 Senses #8

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69 Senses #10

70 Endocrine System Endocrine Glands Ductless Maintain control for a longer duration Examples include adrenal glands, pituitary gland and thyroid gland Exocrine Glands Ducts (tubes) Examples include sweat and salivary glands What is an example of BOTH and exocrine and endocrine gland?

71 Types of Hormones Steroid Hormones Made of cholesterol Fat soluble Attach to receptors in cytoplasm (inside cell) Examples include sex hormones and cortisol Protein Hormones Made of amino acids Water soluble Attach to receptors on cell membrane Examples include hgh and thyroxin

72 Homeostasis-(+) & (-) feedback Hypersecretion = too much of a hormone being released Hyposecretion = not enough of a hormone being released

73 Usually the diploma will give a function of a hormone and then ask which gland produces the hormone described so you need to be able to identify the hormone and then the gland

74 Glands and Hormones Made of 2 lobes: Pituitary (master gland) Posterior lobe stores and releases hormones produced by the hypothalamus Anterior lobe produces and releases its own hormones. Regulated by hypothalamus NOTE: The diploma will notask you to differentiate the hormones produced by the anterior and posterior lobes

75 Human Growth Hormone (hgh) Affects all cells, especially cartilage and bone cells At puberty : A hypersecretion causes GIGANTISM A hyposecretion causes DWARFISM We will talk about the rest of the pituitary hormones during the Reproduction lesson.

76 Adrenal Glands a) Adrenal Medulla (inner gland) Regulated by nervous system Produces norepinephrine (sustain BP) and epinephrine during stress. Functions are sympathetic NS responses: Increased blood sugar Increased heart rate Increased breathing rate Increased metabolism Blood vessels dilate Pupils dilate Peristalsis stops NOTE: The diploma will notask you to differentiate between hormones produced by the adrenal medulla and cortex

77 Adrenal Glands b) Adrenal Cortex (outer gland) Small amounts of sex hormones Aldosterone Increased Na + reabsorption into blood. Released when blood volume and BP are low Cortisol (LONG TERM stress) Amino acids/fats are converted into U Testosterone in females and estrogen in males

78 Antidiuretic Homrone(ADH) Produced by Posterior Pituitary Makes nephron (kidney) permeable to water so water can be reabsorbed back into the blood Released when the body is dehydrated and needs to conserve body water Produces a concentrated urine Diabetes Insipidus body can t produce enough ADH

79 Negative Feedback loop for Release of Cortisol

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81 Endocrine #1

82 Endocrine #2

83 Endocrine #3

84 Endocrine #4

85 Endocrine #5

86 Pancreas (Islets of Langerhans) a) Insulin Released from beta cells when blood sugar levels are high Makes cells permeable to glucose and converts glucose into glycogen in the liver and muscles Effect on blood glucose levels??? b) Glucagon (all the glucose is gone) Released from alpha cells when blood sugar levels are low Converts glycogen into glucose Effect on blood glucose levels???

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88 Diabetes Mellitus Symptoms of Diabetes Mellitus: Glucose in urine (sweet urine) High urine output Low energy levels

89 Thyroid Gland Located in front of trachea Produces 3 hormones: Thyroxine Triiodothyronine Calcitonin Thyroxineand triiodothyronineregulate metabolism (rate of cellular respiration) Thyroxinedecreases blood sugar levels because it increases metabolism

90 Hypothyroidism Release low amounts of thyroxine What happens to excess glucose that can t be broken down? Symptoms include: Weight gain Tired Sensitive to cold Dry skin Treatment??

91 Goiter An enlarged thryroidgland due to lack of iodine in diet (component to make thyroxine). As a result, production of thyroxin is decreased. Thyroid increases in size due to build up of TSH in the thyroid gland

92 Negative feedback loop for normal thyroxine release

93 Hyperthyrodism Release high amounts of thyroxine Symptoms include: Sweating Anxiety Weight loss Heat intolerant Racing heart Bulging eyes Graves disease (in children) Treatment??

94 Calcitonin Released when blood Ca 2+ levels are HIGH 3 functions: Increase Ca 2+ excretion from kidneys Decrease Ca 2+ release from bones Decrease Ca 2+ absorption from small intestines Effect on Ca 2+ levels???

95 Parathyroid Gland Located on top of the thyroid gland Releases Parathyroid Hormone (PTH) when blood Ca 2+ levels are LOW 3 functions: Decrease Ca 2+ excretion from kidneys Increase Ca 2+ release from bones Increase Ca 2+ absorption from small intestines Effect on Ca 2+ levels?

96 Prostaglandins Hormones that have an effect on a small localized area

97 Endocrine #6

98 Endocrine #7 Endocrine #8

99 Endocrine #9 Endocrine #10

100 Endocrine #11

101 Endocrine #12 Endocrine #13 Endocrine #14

102 Endocrine #15 Endocrine #16

103 Answers to Practice Questions Nervous System 1. C 2. D (for THAT neuron need to look at graph) 5. A 6. A 7. C (reflex) 8. D 9. C 10. A 11. D 12. C (fear is an adrenaline type sympathetic response) 13. A 14. A Senses 1. B 2. B (or 314, order no longer matters on diploma, but read instructions carefully) 4. D B 7. C C Endocrine 1. A B 5. B 6. D 7. C 8. A 9. C 10. C 11. A 12. B 13. B 14. A (C is not direct) 15. B 16. A (both groups don t get caffeine, so that would be different. Dopamine is responding variable, not control)

104 Unit A: Nervous and Endocrine Systems Questions? Comments? Next is Unit B Reproduction and Development