Week 3 Lecture Notes Biology 3020
Week 3 Lecture Notes Biology 3020 BIOL 3020-001
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This 11 page Class Notes was uploaded by Maria Martinez on Friday September 11, 2015. The Class Notes belongs to BIOL 3020-001 at Middle Tennessee State University taught by Dr. Miller in Fall 2015. Since its upload, it has received 52 views. For similar materials see Comparative Anatomy of the Vertebrates in Biology at Middle Tennessee State University.
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Date Created: 09/11/15
Week 3 Lecture Notes 3 primary brain swellings vesicles 1 Prosencephalon forebrain 2 Mesencephalon midbrain 3 Rhombencephalon hindbrain 5 brain vesicles 1 Myelencephalon Also known as the medulla oblongata Is essentially a cord extension of the spinal cord to brainstem Composed of tracts that carry signals from the brain to the body A damaged nerve in the part of the brain can result in death Houses nuclei and cranial nerves Nerves VIIXII in mammals Nerves VIX in sharks the telochordia which are thin membranes forming the medulla oblongata are posterior to the choroid plexus is one of the sites Where cerebral uid Will be produced Holds some sensory neurons Facial lobes responsible for gustation Vagal Lobes responsible for olfaction Houses the solitary nucleus a clustering of cell bodies that is associated With the sense of taste in fish Holds the octavolateris a pair of nuclei associated With the lateral system Which is responsible for perception equilibrium and hearing in fish 2 Metencephalon Has 2 prominent features 1 Pons Latin for bridge Grown out ventrally It is the connection between the cerebellum and the medulla oblongata Serves as communication and coordination center between both hemispheres 2 Cerebellum 3 Mesencephalon Associated with involuntary movements Hagfish have no cerebellum Lamprey have a very rudimentary cerebellum Has 2 components 1 Auricles Receive information from the lateral line systems and vestibular portion of the inner ear deal with equilibrium 2 Body Receives mostly sensory information No association with olfaction or gustation Has propiorecptors that wrap around the skeletal muscle fibers to connect with the brain to tell it what degree of contraction is happening Its connections off the cerebellum allow it to integrate information auditory visual to the brain Some fishes have the ability to interpret their electrical output because of the cerebellum called electrical sense The larger the cerebellum the larger the receptors It is enlarged in birds and mammals and becomes folded this is termed folia and increase brain matter surface area which allows more synapses The dorsal portion is called tectum The oor or ventral portion is called tegmentum Contains the nuclei for the oculomotor and trochlier nerves Some of the nuclei are associated with the Vth cranial nerve Some motor sensory activity originates here In fish There are bulges located off the tectum that are associated with visual responses The larger the eyes the larger the part of the optic nerves will be on the brain Below the optic nerves are auditory nerves that receive and sent sound information In mammals anmniotes In the optical lobes and auditory nerves is referred to as the superior colliculi Are associated with eye movements and visual re exes Below the superior colliculi are the inferior colliculi Are associated with hearing and auditory re exes Both of these swellings the superior and inferior colliculi make up the corpora quadrigemina Diencephalon Has 3 distinct regions 1 Epithalamus Contains the habenula which serves as an interface for the limbic and motor pathways Basic emotions like fear pleasure anger are centered here The limbic system is associated hunger and sex drive These pathways sizes will increase in animals with larger habenula meaning they have better memory In birds the small habenula means less developed sense or smell Contains the pineal and parietal complex Are photoreceptive and are also known as the third eye In some fish their functions could serve as actual eyes In mammals the pineal gland is associated with light detection and helps regulation cyclic behavior Has 4 evaginations swellings 1 Paraphysis not much is known about the paraphysis 2 Dorsal sac not much is known about the dorsal sac 3 Epiphysis also known as the pineal organ lizards have well developed epiphysis In mammals is an independent structure 4 Parietal organ also known as the parapineal or the parietal eye Will include a cordia lens and photoreceptor cells Not well developed in frogs Not developed at all in mammals 2 Thalamus all sensory pathways coming from spinal cord are going to synapse in nuclei located in the thalamus In reptiles the thalamus is smaller where as in humans it is going to be bigger Contains large mass swellings found between the thalamus and the 3rd ventricle called massa intermedia 3 Hypothalamus Found in the anterior boundary next to the optic chiasm Gives rise to the infundibulum also known as the pituitary stalk The infundibulum will connect to the pituitary gland that develops from the roof of the mouth in embryo created the anterior pituitary pituitary gland associated with the endocrine system so it deals with horomones posterior pituitary produced oxytocin also produces antidiuretic hormone that conserves uid passing through kidneys this is inhibited when drinking alcohol and that is what causes people to go to the bathroom often because the kidneys aren t ltering the liquid it s just going straight though anterior pituitary Associated with growth hormones thyroid stimulating hormone prolactin follicle stimulating hormone leuteinizing hormone and the Adentrocotropic hormone regulates homeostatic activities contains some olfactory centers contains the tuber cinerium which helps regulate circadian rhythms 5 Telencephalon includes the cerebral hemispheres and Rhombencephalon which includes olfactory tracts bulbs and lobes the bigger the Rhombencephalon the better the sense of smell 4 Central canals enlarged cavities are called ventricles 4th ventricle is going to be in the Rhombencephalon cerebral aqueduct of sylvius is in the mesencephalon 3rd ventricle Is located in the diencephalon lSt and 2nd are within the telencephalon are called the lateral ventricles of the cerebral hemispheres produces some cerebral spinal uid that ows from the central canal to be produced from the posterior plexus in the medulla oblongata Sense Organs Specialized cells responsible for detecting or monitoring changed internal or external changes or stimuli Responsible for translating environmental energy into an electrical impulse neurons at rest are polarized ions of one charge on the outside membrane and different charge on the inside of the membrane When information passes through it it Will depolarize the neuron causing the information to pass through the neurons via electrical impulses all cells of the body can detect stimuli some are just specialized Sensory receptors become transducers a sense organ is formed when dendrites of that sensory receptor neurons are embedded in the tissue Sensory Organs Somatic sensory organs associated With skin going to the skeletal muscle Visual sensory organs Associated With the visceral organs Extrasensory organs monitor external environment Intersensory organs monitor internal environment General sensory organs Wide distribution in the body Deal With touch heat and degree of contraction Specialized sensory organs deal with light touch and equilibrium form sense of olfaction sight gustation General sensory receptors Free naked receptors the dendrites are branched out but nerve endings empty into tissues that aren t specialized associated with pain extreme heat or cold stimulated when swelling from damaged tissue abundant in areas like eyes mouth and intestines Encapsulated sensory receptors dendrites will be enclosed and associated with specialized functions Meissner s Corpuscles sensitive to touch Embuldge of Krause sensitive to cold Corpuscles of Ruffini sensitive to touch Pacinian Corpuscles located in skin joints body Viscera sensitive to pressure Associated receptors dendrites wrap around organs house proprioceptors which wrap around the skeletal muscle so that when it contracts it sends the information to the brain Specialized Sensory Receptors localized in distribution Sensitive to information like light waves or chemicals Specialized for specific stimuli Has chemoreceptors a chemical molecule that will integrate with a receptor which are responsible for two things 1 Gustation associated with the upper part of the tongue or where there are taste buds taste buds acts as transducers fit in the receptors of the sensory cells and that will cause the depolarization of the cells that will send the message to the brain 3 primary cell types that make up taste buds l Basal cells Give support to the Sustentacular and gustatory cells 2 Sustentacular cells Give support to the basal cells 3 Gustatory sensory cells Live about a week and there are replaced Lack axons but when depolarized will link up with a sensory neuron causing a synaptic reaction The sensory neurons are associated with the facial glossypharyngial and vegus nerves There are 5 families of gustatory cells and each will send a different path of electrical voltage to the brain which allows for discrimination between them 1 salt taste is associated with ions 2 sweet taste is associated with sugar and carbohydrates 3 bitter taste is associated with alkaloids 4 sour taste is associated with acids and acid salts 5umami taste is associated With animo acids taste detection is the best in mammals 2 Olfaction associated With the nasal passage has 3 components 1 Olfactory epithalamium the surface layer of nasal passageways has 3 primary cell types 1 Basal cells replenish cells for the Sustentacular and olfactory cells 2 Sustentacular cells gives support for the basal cells 3 Olfactory sensory cells they send information to the brain has a series of dendritic process that have an axon processes that Will travel to the olfactory bulb the dendrite processes are special types of cilia called kinocilia they are not motile there are about 10000 different sensory cells identified so far 2 Olfactory bulb made of mitral cells synapse With axons of olfactory cells that send information into the olfactory tract in fish they are sacs in jawless fish the sacs become fused and just have a single sac and bulb but the tract ways are still paired in sharks water has to move through nasal sacs to smell the water the septum helps the water ow by separating into a division to increase the water ow other fish have extracurrent and internal organs to help the water ow in some fish the water ows to the oral cavity which is an evolutionary in the sarcopterygians eshfinned fish some have external and internal nares nostrils Amphibians have a vomeronasal organ also known as J acobson s organ which is a specialized sac that is associated with pheromone detection the olfactory bulbs are smaller compared to fishes unlike fishes where the nasal passage way is for olfaction and the nasal pathway is for respiration Lizards Snakes Vestibule has a duct nasopharyngeal duct that leads into the body have a more complex nasal passageway vomeronasal organ is separated into pits and located in the oral cavity and used for detecting chemicals for mating or catching prey in snakes the tongue fork has receptors used to sense chemicals allowing it to track prey m contains photoreceptors that sense light are organs formed by different tissues Mammals Birds nasal passageway has hair that allows air filtering to take place warming the air for the lungs and moistening the air so it s not too dry Vomemasal organ is only present in some like dogs and cats and used for the ehmin response located in the anterior end of the palate anterior palatine foramen are openings into the J acobson s organ allowing to detect chemicals use nasal passageways to warm air have really poor sense of smell but otherwise similar to the lizards allows animals to focus or specific cells creating a focus on light this creates an image allows for accommodation which is to be able to focus light at differences in focal points focus is defined as the ability to discern the object being looked at the eyes have the ability to decipher contrast which is defined by detecting different light intensity contrast allows the eye to see color defined as different wavelengths of light the eyeball is similar in anatomy in most vertebrates
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