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BIOL 4260 Midterm: Exam_2_Study_Guide

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BIOL 4260

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Anatomy Exam 2 Study Guide Trachea • Single pipe supported by rings of hyaline cartilage (to stiffen) • Carina- where the trachea divides into the two primary bronchi o Split aligns with the top of the heart and the aorta and vena cava o So the lungs are close to the heart so the lungs can oxygenate and remove carbon dioxide from the blood o A transverse section of the trachea only gives one lumen, once there are two lumen in the transverse cross section, you are in the bronchi • Anterior to the esophagus o The trachea provides support for the esophagus, which is not as rigid as the trachea Bronchi • Left and right primary bronchi o Primary bronchi have hyaline rings like trachea o Right and left primary bronchi are different ▪ Dimorphic according to size ▪ Right bronchi is steeper (25 degrees) and larger in diameter than the left • This makes children more susceptible to choking in the right lung ▪ Left bronchi is about 45degrees • Primary bronchi divide into the secondary bronchi o Secondary bronchi have long cartilage plates • Secondary bronchi divide into the tertiary bronchi o Tertiary bronchi also have cartilage plates o The tertiary bronchi supply a unique lobe of the lung with air • Tertiary bronchi become bronchopulmonary segments (for every one tertiary bronchi there is one bronchopulmonary segment) o Bronchioles are within the bronchopulmonary segment ▪ Bronchioles must be soft so they can move when the bronchopulmonary segment increase or decreases in volume ▪ Only about half a millimeter wide, hard to push air through them • A decrease in lumen size by 1 unit, requires an increase in 1 unit cubed to push air through o Ex. Lumen decrease to 1/2, would require 8 times as much pressure to get the air through ▪ Self-supporting ▪ Smooth muscle for bronchodilation (sympathetic stimulation) • Opening of the lumen of bronchioles ▪ Smooth muscle for bronchoconstriction (parasympathetic) • Collapsing lumen to smaller size when less respiratory exchange is needed ▪ Bronchioles become terminal bronchioles and are surrounded by alveoli o These bronchopulmonary segments supply certain regions of lobes with air • Extrapulmonary or intrapulmonary o Splits occur either inside or outside the lungs o Most primary to secondary divisions are extrapulmonary o At least half of secondary to tertiary are intrapulmonary Alveoli • Between alveolar sac and bronchiole is an alveolar duct o Many ducts per bronchiole • Inside alveolar sac is a volume change • Many hundreds and thousands of alveoli in alveolar sac • The capillary beds surrounding the alveoli is the point of gas exchange o Capillaries increase the surface area of veins and arteries to allow for gas exchange • Elastic tissue surrounds the alveoli so they can come back to shape after inhalation Lungs • Right lung has three large divisions o Superior, middle, and inferior lobes o Middle lobe is more medial o Can have ten tertiary bronchi, therefore 10 bronchopulmonary segments • Left lung o Superior and inferior lobes o Fewer lobes because the left lung must accommodate the heart ▪ Volume is a little less compared to right lung o 8 or 9 tertiary bronchi • Bronchopulmonary segments do not supply regions of the lobes equally o It is dependent on which muscles are used to breathe the air in o they do not completely rid the lungs of air, this would cause the alveoli sacs to collapse ▪ so there is a mixing of stale and new air • Pleural cavities and pleural membrane o Serous fluid in the pleural cavity ▪ Provides some resistance to the lung expanding ▪ When air is stuck between the visceral and parietal pleura, you have a pneumothorax (collapsed lung) • Lung cant expand against the air Respiratory Muscles • Diaphragm o During inhalation it contracts and lowers itself, pulling the thoracic cavity down ▪ Thereby changing the space of the pleural cavity o During exhalation it relaxes and raises itself, allowing the thoracic cavity to go back up to its original position • Intercostal muscles – between ribs o External intercostals – act to pull up on the ribs (elevate them) and expand them ▪ At the articular surface at back of spine, the ribs are rotating against vertebrae and being lifted up by external intercostals, thereby expanding the lateral space of the cavity o Internal intercostals – depress the ribs to aid in exhalation ▪ Much smaller than diaphragm Respiratory Problems • Pneumothorax (collapsed lung) o If the visceral membrane of the lung is penetrated and the alveolar sac is penetrated, air will leak into the serous fluid and a pocket of air will form that the lung cannot expand against, reducing the capacity of the lung to expand • Asthma o Mediated by the quality of air ▪ Poor quality of air can cause constriction of bronchioles (you don’t wanna breathe in too much air of poor quality) o Lumen of bronchioles are reduced by a large amount in asthmatic conditions ▪ The amount of work required to get fluid through a pipe increases by a cube as the lumen decrease in size by one unit Cardiovascular System • Veins always bring blood back to the heart (whether its oxygenated or not does not matter) • Arteries always carry blood away from the heart (whether its oxygenated or not does not matter) • The Heart o We have a divided circulatory system; the heart is split into two halves ▪ One half that pumps blood to the lungs • Deoxygenated blood comes back to the heart from the rest of the body and pumped out to the lungs on its right side ▪ One half that pumps blood to the rest of the systemic circuits • Oxygenated blood returns to the heart from the lungs and pumped out to the rest of the body on the left side o The heart can be viewed as one tube that bends and fuses together at the bends to get the heart itself o Location of the Heart ▪ in pericardial space of the thoracic cavity ▪ the serous cavity adheres to the heard parts of the thoracic chamber and keeps the heart in place ▪ 2/3 of heart lies on the left side of the median plane ▪ Apex of heart points down and to the left ▪ Base of the heart faces T6-T9 vertebra with pericardium, esophagus and descending aorta intervening o size of your heart keeps pace with the volume of the body, an isometric scaling relationship o Pericardium – the membrane that surrounds the heart ▪ Serous pericardium is one mesothelial sheet with two regions: parietal and visceral ▪ Produces serous fluid between them ▪ Parietal serous pericardium lines the inner surface of fibrous pericardium • Lines the pericardial space vertebra with pericardium ▪ Visceral pericardium (epicardium) is the most external layer of the heart wall • Layer of loose connective tissue that supports mesothelium o o Function: ▪ Protects the heart ▪ Prevents heart from sudden over-dilation due to overfilling ▪ Stabilizes vigorously beating heart ▪ Is a closed double-layer of fibrous connective tissue and mesothelium that heart develops into • These connective tissues connect the pericardium to the mediastinum, the bony interior of the thoracic cavity • Acts to anchor the heart in place as you move around o Superficial anatomy of the heart ▪ • From the anterior view you should be able to identify three chambers o Usually the left atrium is obscured ▪ Sulcus splits the left and the right sides of the heart; the two sides are not supposed to communicate with each other o Blood flow ▪ During systoli (compression) the tricuspid valve checks the backflow and pushes blood into the right ventricle and into the pulmonary artery ▪ Then the left atrium draws blood in during diastoli ▪ During systoli the blood is pushed out of the left ventricle intot he aorta ▪ o Conduction system ▪ Coordinates systole and diastole of atria and ventricles to maximize efficient pumping of blood ▪ Recorded by surface electrodes as ECG ▪ Beats from upper right to lower left side ▪ Specialized cardiac muscle cells that conduct a series of action potential in phase along the length of the modified cell system ▪ ▪ Sinoatrial node and atrioventricular node together is the pacemaker of the heart • This generates myogenic stimulus that induces depolarization of muscle cells down the length of the bundles of the modified cardiac cells • It begins in the SA node, once the depolarization hits the AV node, the heart depolarizes from upper right to lower left (dorsal to ventral) o This allows for the proper flow of the heart, contraction of the atria to push blood into the ventricles, then contraction of the ventricles to push blood out of the heart ▪ If the whole heart beat at once, all the blood would be pushed out ▪ Auscultation principles • Heart valves lie roughly in same oblique plane posterior to sternum rd • Plane runs from L 3 sternocostal joint to around mid-sternum at the level of 5 sternocostal joints • Line up the stethoscope with the plane of a valve • Place the stethoscope superficial to chamber or vessel into which blood has passed-basically in line with axis of valve orifice nd o Pulmonary valve: L sternal border in 2 LICS nd o Aortic valve: R sternal border in 2 RICS o Mitral valve: 5 LICS about 9cm L of midline th th o Tricuspid valve: L sternal border in 4 or 5 LICS • You can listen to the sound of the fluid moving through the valves to see how well the heart is working o Pulmonary circulation ▪ the pulmonary arteries brings deoxygenated blood from the right side of the heart to the lungs ▪ then gas exchange occurs at the pulmonary capillaries surrounding the alveolar sacs • oxygen goes into the blood from the alveolar sacs and carbon dioxide leaves the blood and goes into the alveolar sacs to be exhaled ▪ the pulmonary veins then bring the oxygenated blood back to the left side of the heart o Systemic circuits ▪ Arterial system • Blood in the aorta goes to a systemic circuit above the heart or the a systemic circuit below the heart • Blood that goes to systematic circuits above the heart return to the heart via the superior vena cava • Blood that goes to systematic circuits below the heart return to the heart via the inferior vena cava o Aorta ▪ ▪ Ascending aorta • begins at aortic orifice of left ventricle • Just superior to the aortic valves ▪ Aortic arch nd • Around the R 2 sternocostal joint • Connects ascending aorta with descending aorta • Gives off left and right carotid arteries (to the head) and left and right subclavian arteries (to the arms); however not symmetrically o the right arm and right side of the head receive blood from the brachiocephalic trunk o which splits to the right common carotid and right subclavian artery o the left arm and left side of the head receive blood straight from the aorta via the left common carotid and left subclavian ▪ no brachiocephalic trunk ▪ Descending aorta • Descending thoracic aorta o Continues from the aortic arch: thoracic aorta-in the region of T5 – T12 o It has branching arteries that lead to different segments of the body ▪ Indicates in place in early development ▪ Each somite develops into a body segment that is nitrified and oxygenated by divisions of the thoracic aorta • Descending abdominal aorta o From T12 to L4 o Divides into the left and right common iliac arteries o Then division of the iliac to the femoral arteries • Blood Vessels o With the exception of cartilage (which is avascular), no cell is more than a few cell diameters away from a blood vessel, so they can get oxygen, nutrients, remove waste o As oxygenated blood leaves the heart via the aorta, it gets to its destination via a hierarchy of narrowing vessels (arteries), once it gets to its destination and is deoxygenated in the capillaries, it goes through a hierarchy of widening veins until it reaches the vena cava and returns to the heart o Arteries – carry blood away from the heart ▪ Oxygenated or deoxygenated (mostly oxygenated, except for the pulmonary artery) ▪ Arteries then arterioles then capillaries o Veins – carry blood back to the heart ▪ Oxygenated or deoxygenated (mostly deoxygenated, except the pulmonary vein) ▪ Veins then venules, then capillaries o Capillaries – smallest blood vessels ▪ Exchange of molecules between blood and tissue fluid ▪ Gaseous exchange with alveoli ▪ Return loop: capillaries then get larger and head back to the heart via venules then veins ▪ So narrow they can barely fit 1 RBC (great for gas exchange) o Structure ▪ All blood vessels (except the smallest, less tan about 100microns) have a similar general histologic structure • ALL have the inner tube, it is the outer layers that distinguish them from one another • 3 layers or tunics o Tunica interna (intima) o Tunica media o Tunica externa • Capillaries only have one layer tunica interna o Only about a cell thick (great for gas exchange via diffusion) o Internal tunica in capillary is similar in quality but not as thick as the internal tunica in arteries and veins ▪ ▪ ▪ Tunica Interna • Inner lining in direct contact with blood • Composed of a single layer of squamous epithelium sitting on a basement membrane o Large cells • Beneath the basement membrane is the subendothelium o Loose connective tissue and smooth muscle cells • No elastic tissue and no support, just endothelial cells o So capillaries have no support at all o So how does the lumen stay open, constant flow pressure which gives stress against the wall of the capillary ▪ Tunica media and tunica externa • Have rather substantial support in the form of collagen fibers and elastic layers o Elastic layers give the vessels their rigidity • Tunica media o Consists of several layers of smooth muscle o Between the smooth muscles cells are variable amounts of elastin fibers and fine collagen o Larger arteries and veins have an outer elastic lamina ▪ Sheet that wraps around the media that gives extra stiffness and spring like quality o Smooth muscle regulates diameter of lumen ▪ Differences between veins and arteries • The lumen can change diameter much more in an artery than in a vein o Because there are more smooth muscles in arteries than veins o The tunica media in an artery are much thicker in arteries ▪ Allows for a greater lumen change o This also requires a thicker elastic membrane in arteries so they can stretch and change diameter ▪ Makes them more rigid ▪ More elastin means that you can store the pressure from the hearts along the walls of the arteries • This helps keep unidirectionality and pressure at all times • This is why you have a blood pressure even when your heart is at rest (diastole) • Arteries have no valves because the blood pressure in arteries is high enough that there is no backflow of blood • A smaller lumen causes an increase in pressure in the arteries, this makes the blood in the arteries travel with higher velocity o This is good because the blood needs to get to the tissue fast ▪ Elastic arteries (>10mm) • Also known as conducting arteries – conduct blood to medium-sized arteries • The largest arteries closest to the heart • Includes the aorta and its major branches • Subjected to strong pressures from systolic contraction • T. intima: thin, consists essentially of the endothelium o No different from capillary • T. media: thickest layer with many concentric layers of elastic laminae; some smooth muscle and collagen fibers o This is where the energy is stored • T. adventitia thin: no distinct external elastic lamina, blends with connective tissue o Large vessels did need as much connective tissue because they are more rigid ▪ Large Veins (>10mm) • Typical structure • Larger diameter • Thicker endothelium (T. interna) • Tunica media is thin • T adventitia is thick, bundles of smooth muscle and collagen and elastic fibers o This makes sense because it does not have its own support, like the artery has the thick T. media, so it needs a thick T. externa • Examples: vena cava and jugular vein ▪ ▪ Medium (or muscular) arteries 2 to 10mm • Transport blood to organs • Circular in shape, includes most of the named arteries • Less elastic material and higher smooth muscle content o So you cant store as much energy from the heart, but the increase in muscle helps control the size of the lumen and control blood flow • Prominent internal elastic o Thin in diameter, so cannot store as much energy as the large arteries • Less prominent external elastic lamina • T. intima is thin and typical • T. media is thick (muscle) (the thickest) • T. adventitia is thick o External elastic lamina and typical connective tissue, and vasa/nervi vasorum vasorum • Capable of great vasoconstriction/vasodilation to adjust rate of blood flow ▪ Medium vein (2-10mm) • Variable shape • Typical three layers o T. intima: endothelium and thin subendothelial layer ▪ Minimal internal elastic lamina o T. media: is mainly smooth muscle, but thinner than in arteries ▪ So less of an ability to vasoconstrict or vasodilate o Thick adventitia…forms bulk of wall • Valves can be found in medium veins o Prevent backflow ▪ Backflow is a problem in medium veins because gravity and the decrease in pressure o They can be found in the thoracic chamber o Not in the legs because as you walk, the muscles in your legs push the blood through (acting like a heart) ▪ Small arteries and arterioles • Small arteries: (0.1mm to 2mm) o Have up to 8 layers of smooth muscle layers in tunica media o Inner elastic lamina present; external elastic lamina inconsistent o Less elastic and much less effective at storing the energy of the heart • Arterioles (10 to 100 microns) o 1 to 2 smooth muscle cell layers in tunica media o Internal elastic lamina inconsistent o Thin adventitia o Become thin enough at the point of becoming capillaries to barely fit one or two red blood cells ▪ Small veins and muscular venules • Small veins: (.1 to 1mm) o Smooth muscle layer 2 to 4 cell thick ▪ Hardly any muscle o Adventitia thicker than media ▪ This distinguishes it from small arteries o Valves (like medium sized veins) • Muscular venule o 10 to 100 microns o No inner elastic lamina o 1 to 2 layers of smooth muscle in media ▪ Very flaccid, will collapse when cut o Tunica adventitia thicker than media o Nothing rigid to hold them open ▪ If heart stops beating, venules will collapse because of no support Nervous system • Segments of the human body are not innervated by just one spinal nerve, we have nerves projecting away from the spinal cord, in many cases (except for thoracic) they form plexuses o These spinal nerves project out of the intervertebral spaces o Plexuses form when individual spinal nerves that protrude from a given vertebrae, join with adjacent spinal nerves (anastomosis=joining of individual nerves to make one) o After the nerves meet and form a plexus, you have the trunk o The thoracic region does not have plexuses, we have ribs that represent our segments in our thoracic anatomy, ribs are innervated by their own individual spinal nerves • There are four nerve plexuses: o Cervical o Brachial o Lumbar o Sacral • Cervical Plexus (C1-C5) o Consists of cutaneous and muscular branches o Cutaneous branch innervates: ▪ Head ▪ Neck ▪ Chest o The cutaneous branches go to the skin o The muscular branches go to the neck, head, and dorsal chest • Brachial Plexus (C4-T1) o The immediate nerves emerging from C5 to T1 are the: ▪ Superior trunk ▪ Middle Trunk ▪ Inferior Trunk o These trunks all merge to form the lateral cord o o the three trunks come together to form the lateral cord • Lumbar and Sacral Plexuses (often grouped together) o T12-S4 o Also called the lumbosacral plexus • Lumbar Plexus nerves o Genitofemoral nerve ▪ Anastomosis of a few spinal nerves that innervate parts of the genital system and inside of the thigh o Lateral femoral cutaneous nerve ▪ Innervation of the cutaneous parts of the side of your legs o Femoral nerve ▪ Innervation of the anterior part of the leg ▪ Anastomosis of two nerves from the lumbar region ▪ Motor and sensory • Sacral Plexus Nerves (largest plexus in terms of cross sectional area) o Sciatic nerve (branches to form the common fibular nerve and the tibial nerve) ▪ Anastomosis of the nerves from L5 down to the cranial spinal nerves of the sacrum ▪ Innervation deep within the legs ▪ Very thick ▪ Innervation of the posterior of the leg ▪ Motor and sensory ▪ The reengineering of the hip to be bipedal, has resulted in weird musculature; the Piriformis • The Piriformis can have two or three divisions, the sciatic nerve can pass through these divisions and when the muscle pumps, it can squeeze the nerves and cause sciatic symptoms o Pudendal nerve ***Nerves that go to muscle are not only for motor, they are also for proprioception, which is feeding back about the positional state of your muscle (how you know where the muscle is in relation to other body parts) • Reflexes o Afferent is from sensory nerves to the CNS o Efferent is the CNS to the sensory organ o Inner neuron connects the afferent and efferent and the CNS o o Monosynaptic system: one sensory nerve affects a few muscle fibers o Polysynaptic system: one sensory nerve affects MANY muscle fibers with the help of interneurons o Another type of system: proprioception ▪ This is your body’s ability to know where a body part is, sense a change in muscle length ▪ As a muscle stretches or shortens, it send information to the CNS as action potential telling the body that the muscle needs to contract or relax the muscle • How we control where our muscles are going without thinking about it o o • Sensory and motor Tracts o Motor tracts (efferent, form CNS to muscle) ▪ CNS transmits motor commands in response to sensory information ▪ Motor commands are delivered by the: • Somatic Nervous System (SNS): directs contraction of skeletal muscles o Voluntary • Autonomic Nervous System (ANS): directs the activity of glands, smooth muscles, and cardiac muscle o Non-motor components of peripheral body o Rearrangement of Tetrapod System: • We are derived primates o Once had different musculoskeletal architectutre especially in relation to the trunk o Rearrangement of thorax, lumbar system, etc. • Development is crucial in limb formation – important in our reformation as a human species o explains why they look different than tetrapods o we are much different than fish o our limbs are much different than even the typical mamal o we have extremely dexterous limb system, especially arms Outline • vertebrate adaptations: adaptations for function o supporting the mass of the viscera (whats inside rib cage and stomach) o supporting the body enough so that locomotion is possible ▪ if spine and axial skeleton aren’t stiff enough  not enough support – could not locomote ▪ if it was too stiff it would not be compliant enough to move us along and store energy • Vertebrate number: number of vertebrate mamals have o Largely invariant number for primates o Primates have a similar arrangement for vertebrate number o Subtle differences across primates o Differences among the human species ▪ Most of us have the same number of vertebrate ▪ Every once in awhile someone has extra, tiny, vervical vertebrae but this is very ratre • Rib cage shape: that has changed in our evolution • Bipexalism: all of this is related to our bipedalism o There are not many organisms that walk on two legs o There are other types of animals that do (birds) o But VERY FEW MAMALLS o Our shape related to ur ability to walk on two legs Axial Skeletons of Vertebrates • Largely the same: modifications of this system have resulted in important functional changes o Form- function relationship o All vertebrates have the same geheral body plan because we come from the chordate lineage • Chordates: flexible rod o We have a flexible rod down the axis of our body o At the bgining of development the flexible rod looks like achordate derivative- looks like a notochord o Mesodermal derivative which runs down the length of the body o Vertebrates have elaborated on this form to surround this rod and replace it functionally with bony or cartilaginous vertebrate • Vertebrates: bony or cartilaginous vertebrae o Cartilaginous orgaanisms: sharks, skates etc ▪ Lack ability to ossify cartilidge into bone o all chordates have flexible rod ▪ in most vertebrates the rod is segmented and inserted between vertebrae as intervertebral disks ▪ functionally work together to serve the same purpose: stiff rod down the axis of the body • used to support the viscera • important for locomotion o tetrapods: lateral flexion, expanded ribs to strengthen body wall, sternum to anchor ribs ▪ lateral flexsion: expands the ribs as they move ▪ there is no undulation down the stiffened rod ▪ locomotion is different: flexion is associated with movement of libs, not unudulation (sending a wave down the complex to start locomotion) ▪ expanded ribs: as you locomote viscera aren’t jostling around ▪ sternum anchors ribs and holds onto the viscera • protect mass of organs as we swing our bodies back and forth to walk o mamals: a-p flexion, suspension architecture ▪ mamalls have taken this terrestrial gate and move mass by generating ground reaction force • friction of foot against ground • power of hip and legs to move forward ▪ early tetrapods: gates were diplaced laterally; viscera needed to be held in place – that’s why we got a sternum ▪ in mamals there was a distinct transition: rather than having lateral flexion, now we have anterior posterior extension and compression • mamalls put their legs and arms underneath their body • requires different forms for function • have a-p flexion, wich we have elaborated on • mamals still require suspension architecture but rather than the viscera swinging back and forth with the gate it is largely staying in line with the body and only needs to be supported dorso-ventrally to prevent it from sloshing back and forth Fish Swim o fish swim as early chordates would have
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