The Anatomy Lymphatic System (Fig 23-1) Continuation of the cardiovascular system Composed of vessels Have same layers as arteries and veins Tunica interma Tunica media Tunica externa Delivers lymph Lymph: excess tissue fluid, interstitial fluid Similar to plasma but lacks cells and proteins, only the fluid Plasma forms tissue fluid which forms lymph returns fluid to the blood vascular system no pressure system 2 cell types 1. Lymph Cells/Lymphocytes Most important One of the white blood cells Produced by lymphatic system Some produced in bone marrow 2. Macrophages Large phagocytic cells Structures Categorized into 1. Lymphatic tissue 2. Lymphatic organs Monitor, alter, and filter lymph Filtration probably most important Specific stem cells are present which help to produce the lymphocytes Lymphoid tissues Tonsils Galt Lymphoid Organs Thymus Spleen Lymph nodes Three major functions 1. To maintain blood volume Adds fluid back into plasma to keep the volume of plasma at a certain level 2. Homeostasis Maintenance of chemical levels within the body 3. Production and distribution of lymphocytes Play a role in our immunological system Vessels start out with capillaries: lymphatic capillaries or terminal lymphatics
Capillary beds associated with these Lymphatic capillaries differ from blood capillaries (Fig 23-2) Blind ended, not connected to anything Not a circulatory system Larger diameter than other capillaries Thinner walled No basement membrane Cells connected to one another very loosely Usually look collapsed b/c no pressure to keep them open still endothelium like blood capillaries overlap and can open quite wide to act like a one way valve fluid outside the capillary passes through valves into the lymphatic capillaries bacteria and viruses can get into the lymphatic capillary macrophages help to get rid of the bad things that get into capillary very permeable, more so than blood capillaries allow fluid to pass very readily COP: colloid osmotic pressure Can't draw all fluid in, only gets ~90%, 10% needs to be picked up and carried back to the blood vascular system by lymphatic system 72% of blood plasma is filtered out into tissue spaces per day (3.6 liters approx.) At any point in time there is always a liter of tissue fluid in your body As new fluid is pushing out, it washes the old fluid away, always a turnover Allows for exchange between cells If tissue fluid isn't pulled out, we get swelling. Get anema Congestive heart failure doesn't allow fluid to get back in Lots of swelling within ankles and feet mostly Capillaries carry fluid into larger vessels which then join together to form trunks Trunks come together and form ducts How does lymph flow without pressure? (Fige 23-3) the lymphatic vessels have valves More valves in lymphatic system than in veins Skeletal muscle pump When muscles contract, they push fluid from one compartment to the other 2 categories of lymphatic vessels MAJOR LYMPH VESSELS 1. Superficial lymphatics more of a surface type structure Found in three places 1. Subcutaneous tissue or hypodermis 2. 3 membranes: mucous (lining digestive, reprod, urinary systems), serous membranes (pericardium, pleural),
3. 2. Deep lymphatics Drain muscles and organ systems Deeply placed Ducts Thoracic duct Trunks come into it from side and below Drains of body: entire left side of body and right side of body below diaphragm Right lymphatic duct Drains of body: upper right side of body Where left internal jugular and left subclavian veins come together: where the ducts empty and dump back into the blood plasma and body Lymphocyte (fig 20-5) Blood cell Most abundant of the blood cells: red blood cell/corpuscle Derived from the bone marrow Called erythrocytes: meaning red cells Biconcave discs (kinda like a dog bone) Thinner in middle, thicker on the edges Primarily for gas transport O2 CO2 Also CO Most common 8-8.5 mmeters in diameter Thrombocytes: platelet Cell fragments Pieces of a large cell found in bone marrow Megakaryocytes: large nucleated cell, large nucleus as well Pinches off pieces of cytoplasm which become platelets Platelets involved in clotting mechanism White cells 2 categories 1. Granulocytes Nutrophil: neutral to stain, has an inifinty for Most common of the white cells Make up about 65% of the white cells Phagocytic Have a multi lobed nucleus Eosinophil: acidic stain that turns things red/orange Multilobated One nucleus
Also phagocytic for anything that is tied or connected to an antibody About 3.5% of white blood cells Basophil: basic stain, bluish purple Release chemicals at sites of infection to attract other cells to that site Can get out of the blood vascular system Can get into connective tissue where they're known as MAST cells: basophils that have gone into tissue from out of the blood Least numerous of the white cells: less than 1% Agranulocytes: without granules Monocyte Largest of the white cells Phagocytic Mobile Can stick to surfaces of things: have treadlike threads coming off called filopodia (thread foot) Large U-shaped nucleus 2-8% of the white cells Lymphocyte 20-30% of the white cells Almost all nucleus Found primarily in the lymphatic tissues and organs Also sometimes free in the blood Provide for specific immunity: involved with the immune system 1. T-cells: originally produced in the thymus Move to other tissues and organs and thymus begins to shut down Cytotoxic T-cells: produce toxins against foreign cells like bacteria, viruses, etc : involved in cell mediated immunity b/c cells are actively involved Helper T-cells: work with other lymphocytes Supressor T-cells: work with other lymphocytes Memory T-cells: retain a memory to a particular antigen ---> antigen: foreign substance such as a cell, protein, sugar, lipid, etc 2. B-cells: bone marrow derived Stimulated by the presence of an antigen to become activated When activated, called plasma cells Responsible for immunoglobulins: IGs: antibodies which attack a foreign substance called antibody mediated
immunity/humeral immunity: mechanism that causes tissue rejection b/c of someone else's antibodies Memory b-cells: small number of the bcells, activated when exposed to an antigen; retain memory to the antigen they have been exposed to: how vaccines work, get a little bit of the antigen in the vaccine and form antibodies and then years down the road, the memory b-cells remember this and then it can be fought 3. NK cells: natural killer cells: also bone marrow derived Same basic function as cytotoxic t-cells Attack foreign materials, and normal cells filled with virus Some think it's a cytotoxic t-cell but has one function that the cytotoxic t-cells don't have: WILL attack and basically destroy mutated cells 2. Leucocytes: white cell Lyphoid Nodules (fig 23-8) Lymphatic tissues and organs filled with lymphocytes Lymphatic tissues are aggregates of lymphocytes and form structures called nodules Does not have a membrane or capsule around it Nodules are found generally in aggregates/groupings Tonsils 4 different Lingual tonsils: base of tongue Palatine tonsils: on sides of palate Pharyngeal tonsils: upper area of pharynx adnoids Tubol tonsils: associated with the pharyngeal tonsils Wrap around the auditory tube Can cause ear infection if pharyngeal tonsils push down on tubol tonsils which squish the auditory tube All 4 Form a ring of tonsils Galt: gut associated lymphatic tissue Found in intestines Can be found as aggregates and individually If aggregates, called Peyers Patches Individual nodules: solitary Malt: membrane associated lymphatic tissue nodular structures: not surrounded by a capsule or membrane What is a lymphoid organ? Aggregate of lymphocytes surrounded by a capsule Many lymphoid organ structures called lymph nodes Lymph nodes associated with lymph vessels Have them all along your body
In center of nodular structure we have a germinal center Contains lymphoblasts Derived from the bone marrow Most of lymphocytes produced in nodules and nodes Lymphoblasts produce b-cells Cortex of nodular area T-cells formed in a pericortical region: around the cortex Lymph node: filters lymph Afferent vessels: go into the lymph node Carry lymph into it then the lymph node filters it As lymphocytes move through the lymph node, macrophages remove "bad" stuf Opposite side: efferent vessel: carries lymph away from the node Will be filled with lymphocytes When you get a cold, you get a sore spot under your neck Lymph nodes which are filtering virus When it's sore, it's trying to filter Few areas of the body with large amounts or aggregates of lymph nodes Neck: cervical nodes Axillary nodes: in the armpit Inguinal nodes: in the groin Notice it more when these are sore because it's a large aggregate Thymus gland (fig 23-16) Sits above the heart Behind the menubrium of sterum Original place of production of t-cells Only a small number of t-cells get out of the thymus Only 5% of the t-cells in the thymus get out, over 90% die there Called t-cells because they're originally from the thymus T-cells are not active in the thymus gland As we age, the thymus gland shrinks Involution Function of the cells moves to other parts of the body Sternum Uppermost: manubrium Spleen Largest lymphatic organ Sits on the left lateral border of the stomach Has several functions, most of which relate to the spleen directly 1. Destroy and remove abnormal and old red blood cells Has macrophages, etc 2. Stores iron Red cells have hemoglobin and iron is a part of this Hemoglobin broken down with the red blood cells
Some of the iron is eliminated in the liver some is stored 3. To store blood Can store up to 1/6 of your blood volume, about 1 pint If you remove the spleen, wouldn't be detrimental to the body This is the only function that can't be restored if you remove the spleen 4. Initiates the immune response Causes b and t-cells to come out All the blood in the spleen is where all the antigens end up so it can do this quickly If the spleen is removed, other lymph nodes take over that immune response Nervous System (Fig 13-1) Central Nervous System (CNS) Brain and spinal cord Peripheral Nervous System (PNS) All the nerves Nerves form different anatomical pathways throughout the body Subdivided into 1. Afferent division Sensory Information carried to the CNS 2. Efferent division Motor Carries info away from CNS to the periphery Further divided into 1. Somatic NS (SNS) somatic, body Related to the skeletal system Voluntary 2. Autonomic NS (ANS) Automatic Involuntary Two parts: 1. Sympathetic NS Fight or flight system 2. Parasympathetic NS Vegetative function Not doing anything really... ...> still have aspects working but not ready to fight or flight Primary cell type: Neuron (fig 13-3) Cell body: soma Contains the nucleus, ribosomes, organelles, mitochondria, etc Small pieces of RER (rough endoplasmic reticulum)
NISSL bodies: does everything that RER does Dendrites Receive information from other cells or from outside environment Afferent fibers Axon Nerve fiber Efferent fiber Carry information from soma out to where it will function Synaptic Terminals Affect other cell types: Neurons Muscle cells to move Gland cells to secrete On certain neurons, the dendrites are receptors When talking about neurons The axons of neurons are covered by a fatty lipid called: myelin Said to be myelinated Protects, insulates, and it facilitates the nerve impulse The more myelin, the faster the impulse goes Axons are the longest process on most neurons Can be up to a meter or more in length Classify neurons by Structure 5 types 1. Anaxonic neuron Without an axon There is still an axon but v. difficult to tell axon from dendrite Motor type axons Confined to the CNS 2. Unipolar Rounded cell body Single process coming off soma Will then split into 2 Sensory fibers Also primarily embryonic but are found in adult 3. Bipolar Rounded soma but process coming off each side Dendrite on one side, axon on other Taste buds, in the ear Places with specific sensory fuctions Sensory fibers - afferent 4. Pseudounipolar
Modified bipolar Two processes coming off with an axon and a dendrite Looks like a unipolar kind of Sensory fibers - afferent 5. Multipolar Many processes Generally only one axon Sometimes find a branched axon Lots of dendrites Motor Found going from the CNS out to the periphery Efferent Function 1. Afferent (sensory) From the periphery to the CNS 2. Efferent (motor) From the CNS to the periphery 3. Interneurons (association, internuncial... nunci: messenger) Neurons that connect other neurons together, act like messengers Confined to the CNS Axonic neurons are interneurons Some mulitpolar neurons as well For every 1 afferent, there are 10 efferent and 200,000 interneurons Secondary Cell Types (Fig 13-4) Glial Neuroglia: cells (glia: glue) Bind things together, fill, pack, hold neurons in place Not nervous cells, more like CT Do not function as a neuron functions Several types of glial cells 1. CNS glial cells Macroglia Large glial cells 1. Astrocyte Star shaped cells Largest glial cells Several functions but primary is: to maintain the blood-brain barrier Regulates what gets into the brain from the blood vascular system One thing it can't stop is alcohol Two Types of Astrocytes 2. Oligodendrocytes Macroglia
Smallish dendritic cell Produce myelin in the CNS Wrap around axons 3. Microglia Phagocytic cells Get rid of cell debri Ameboid: capable of movement Only cell able to move within the CNS 4. Ependymal Cells Lining cells Line cavities of the brain 4 cavities: ventricles of the brain In the ventricles, form a choroid plexus Produces cerebrospinal fluid (CSF) Also line interconnecting channels On the free surface of this cell: cilia Keep fluid in constant motion so it doesn't stagnate 2. PNS glial cells 1. Satellite cells Encapsulate around neuron somas Protect Also form a capsule around a group of neuron soma: ganglia Regulate gas exchange, nutrient exchange, and neurotransmitter levels around neurons in ganglia 2. Schwann cells (fig 13-8) Produce myelin Just like oligodendrocites but they are peripheral and oligos are central Wrap around the axon forming a myelin sheath Can wrap around more than one axon at any point in time Neurilemma: forms a covering around the axon (neri: nerve, lemma: covering) Terms Nerve: a clustering of axons or nerve fiber (nerve fiber = axon) in the PNS PNS structure Tract: clustering of axons or nerve fiber in the CNS CNS structure Most obvious in the spinal cord Nucleus: aggregate of neuron somas in the CNS Particularly in the brain Ganglion: aggregate of neuron somas in the PNS Ganglion: aggregate of nuclei in the CNS Spinal Cord 18" long on average
Stops at the level of the first lumbar vertebrae 2 areas where the spinal cord is enlarged Cervical enlargement b/c the nerves going to the pectoral girdle all come off at that point lumbar enlargement supplies the pelvic girdle and the lower extremities where spinal cord terminates, it tapers down tapered end: conus medullaris (conus: cone-shaped, medullaris: marrow) filum terminale: attaches in the sacral area gives spinal cord support and keeps it in position 31 pair of spinal nerves: right and left Have a double connection to the spinal cord Called roots: the connections to the spinal cord Posterior side: dorsal/posterior root Contains sensory fibers dorsal root ganglion all of the somas are in this ganglion anterior side: ventral/anterior root where they go out is the intervertebral foramen that's where they become spinal nerves grows until you're about 4 and then growth slows but the vertebral column keeps going each spinal nerve still has to go out of the correct foramen dorsal and ventral roots then have to grow and stretch down cauda equina: (horse tail) where all the roots come together where they're stretching down SECTIONAL ANATOMY OF A SPINAL CORD Right in the midline: anterior median fissure Small groove, wider and deeper than a sulcus Posterior median sulcus Small groove Posterior median sulcus and the anterior median fissure help divide the spinal cord into right and left sides Butterfly shaped area: gray area Composed of soma, cell bodies of neurons, dendrites, and unmylenated axons Organized into regions: 1. Posterior/dorsal Horn Sensory information 2. Anterior/ventral Horn motor??????? information going out to body 3. Lateral horn Fits between other 2 horns
Autonomic; information to the internal organs Middle of gray area: central canal Connected to a ventricle in the brain Ventricle filled with CSF Fluid allows a little bit of diffusion so that it can get nutrients in and waste out Helps to keep the spinal cord open and stiff Around the gray area: white matter Composed of mylenated axons and glial cells Organized into columns Right and left ones These columns made up of tracts Groupings of axons 2 types of tracts Ascending: sensory going to brain Descending: coming from the brain, motor Columns are both types Three areas where the right and left sides of the spinal cord are in communication Information exchange takes place here Called commissures: united Named according to location and what they're in 1. Posterior gray commissure 2. Anterior gray commissure 3. White commissure Spinal nerves become branched after leaving the vertebral column Each spinal nerve has the same grouping of branches Rami (plural) ramus (sing.) 4 basic rami 1. Dorsal Ramus Posterior side Nerve fibers (sensory and motor) in this are going to muscles and skin on the posterior side Also innervates the joints 2. Ventral Ramus Goes to muscle and skin on the lateral and anterior surfaces 3. Rami communicantes (communicating ramus) Splits into 2 White and gray ramus - white has myleinated fibers, gray has unmyleinated fibers Connected to the internal organs Autonomic
4. Meningeal Ramus Protective membranes that come off and then go right back inside and innervates intervertebral discs and ligaments, periausteum Fig 14-9 each spinal nerve goes to a particular part and innervates a specific region Skin on the surface also involved so very easy to recognize Dermatomes: sections of the skin that are innervated by a specific spinal nerve Aids in diagnostic activity Evultion: once it's pulled out, it's gone Only thing to do is surgery to transfer nerves to gain function again Shingles: re-exposure to chicken pox Light case of chicken pox, virus goes and sits in a specific nerve, if you're re-exposed to chicken pox, shingles explodes The Brain 6 major divisions of the brain 1. Cerebrum ~80% of the brain Higher brain activities: thinking, reasoning, understanding Can also be called the telencephalon: (complete) 2. Diencephalon :(second part of brain) Involved in sensory relay of information and some autonomic functions 3. Mesencephalon: (middle area of brain) Primarily involved with reflexes 4. Pons: (bridge) Connects the cerebrum to the cerebellum Involed in involuntary controls, self regulatory 5. Medulla oblongata (oblong marrow) Myelencephalon: (marrow) Involved in autonomic control 6. Cerebellum: (little brain) Pons and cerebellum collectively called the METENCEPHALON: (behind brain) Involved in balance and equilibrium #'s 3, 4, 5, are called the Brain Stem More like the spinal cord than the rest of the brain Have gray inside and white matter outside, etc Cerebrum of the brain: Silvery coating: the meninges: membranes that cover and protect the brain and spinal cord Divided into 2 parts, each part a hemisphere (right and left)
Divided by the longitudinal fissure Deep and wide In the fissure is a fold of the meninges: Falx cerebrei: (falx: sickle, instrument used to cut plants) Keeps the brain where it should be Allows you to shake your head and the brain moves with your head Gray matter on the surface not very thick, but allows for more information to be there Surface of the cerebrum is folded and has valleys Folds: gyrus (sing.) gyri (pl) Increase the surface area Valleys: sulci (pl) sulcus(sing) Deep sulci: fissures Each cerebral hemisphere divided into 5 segments 1. Frontal lobe Most anterior Separated from the parietal lobe by central sulcus Precentral gyrus involved with all motor activity Several functions: Voluntary motor control Initiate motor activities Motivation Short term memory Pre planning In left frontal lobe, there is an area called Broca's area Speech center Allows you to speak 2. Parietal lobe (parietal: wall) Immediately posterior to the frontal lobe, behind central sulcus Post-central gyrus Sensory information Compares information to new sensations to ones its already learned Ex: precentral gyrus allows you to pick up a beverage, post central gyrus tells you if it's hot, good, etc 3. Occipital lobe (occipital: back of brain) Separated from parietal lobe by a parieto-occipital sulcus Relatively short Primary visual cortex of the brain Visual association area
Takes what we see, pulls it from retina to occipital lobe which compares it to past experience, and we know what it is from past experience 4. Temporal lobe Beneath parietal and frontal Separated from frontal and a little of the parietal lobe by the lateral sulcus Primary auditory cortex and association area Also involved in converting short term memory to long term memory Also contains speech-comprehension area/language sensor Wernicke's area Allows you to understand what is being spoken to you or what you are reading 5. Insula lobe Located inside the lateral sulcus Has gyri and sulci just like rest of cerebrum Primary gustatory center/association center Taste center When you look at cerebrum, we use mapping structure called homunkulus: little man. Inverts your body Shows relationship of body structures to brain In the brain, we have ventricles: cavities Total of 4 ventricles One in each cerebral hemisphere called lateral ventricles or ventricle 1 and 2 Inside each of the ventricles is a choroid plexus, which produces CSF Each of these areas are interconnected CSF is supportive Diencephalon: second region of brain (developmentally) 3 parts 1. Thalamus Relay and processing centers for sensory information All sensory information except olfaction(smell) goes into and through this center Forms the walls around the third ventricle 2. Hypothalamus Hypo: beneath, beneath thalamus Forms floor of third ventricle Key part of brain Functions in emotion, behavior, control body temp, homeostasis (controlling both the nervous and endocrine system) Pituatary Gland
Controls all other gland structures Optic chiasma Where the 2 optic nerves come together Allows brain to put images from right and left eye together 3. Epithalamus Above thalamus Roof of third ventricle Contains pineal gland/ pineal body Produces a hormone called melatonin Triggers onset of puberty w/o melatonin, there's no puberty controls circadian rhythms sleep/wake cycle can be thrown off by environmental factors (jet lag, seasonal affective disorder, etc) Brain Stem Made of 3 parts 1. Mesencephalon (mid brain) Important for visual and auditory reflexes Corpora quadrigemina Bodies four twins Four small bodies that are paired Superior colliculi (pair) Visual information Inferior colliculi (pair) Auditory information Cerebral peduncles Fiber tract Curled toe Allows for 2. Metencephalon Pons Relay sensory info to cerebellum and thalamus Subconscious somatic and visceral motor centers Controls involuntary respiratory activity Cerebellum (not part of brain stem) 3. Medulla Oblongata (myelencephalon) Was thought to all be marrow of brain Involved with autonomic control of heart rate Normally controlled by SA node but can slow down/speed up heart Involved with respiratory rate
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Controls the pons Relays sensory info to thalamus Autonomic centers for regulation of visceral functions such as cardiovascular respiratory and digestive activities Decussation Info going into brain passes through here Right side of the brain controls left side of body, etc: contralateral control Where this information crosses over is decussation Contains the 4th ventricle and has choroid plexus Metencephalon: behind brain & Cerebrum Cerebellum impt in equilibrium and balance in inner ear Also impt for fine tuning muscle activity Gets info from muscle and cerebrum so can correct muscle if its not doing what its supposed to do Lose this comparator function when you drink Involved in procedural memory Learned series of procedures or events Typing on computer Riding a bicycle Gray matter on surface and white matter internal like the cerebrum Has gyri and sulci but they're smaller than those of the cerebrum Only run in one direction, pretty much parallel Meninges Protection of brain and spinal cord Also called meninx: single membrane Outermost of meninges: dura mater Thickest Strongest Has 2 layers to it Outermost layer: endosteal membrane Firmly applied to the bone's inner surface Parietal, frontal, occipital, etc bones Meningeal layer: second layer Folds down into the falx cerebri Around the spinal cord, there's a gap: epidural space Women giving birth get an epidural which goes into this space and deadens the nerves Spinal tap goes here Arachnoid membrane Coming off are arachnoid trabeculae Form a space called the subarachnoid space Find blood vessels here
Coming out of the arachnoid membrane are little pockets going into sinuses Arachnoid granulation: little pocket CSF gets reabsorbed here Pia mater Delicate Covers surface of brain and spinal cord like it's painted on 12 pair cranial nerve Part of PNS Be aware of number, name, and type!! 3/12 go to eye