Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
77 Cards in this Set
- Front
- Back
|
What is the difference between granulocytes and agranulocytes? |
Granulocytes contain protein granules in cytoplasm. Agranulocytes have cells which may further differentiate/proliferate and with a longer life span. |
|
|
Lymphoid progenitors |
Stem cells Forms lymphocytes (T and B cells) Migrate to lymphoid organs (spleen/thymus) for further maturation |
|
|
Myeloid progenitors |
Forms multiple different specific progenitors and precursors Give rise to ALL blood cells EXCEPT Lymphocytes Migrate into blood as mature cells |
|
|
Red bone marrow |
Active bone marrow (hematopoiesis is occurring) All fetal bone marrow is red |
|
|
Yellow bone marrow |
Inactive bone marrow (Hematopoiesis is not occurring) Can be converted to red marrow in cases of severe bleeding or oxygen deprivation |
|
|
Stroma of bone |
Reticular fiber network of bone marrow |
|
|
Hematopoietic Cords |
Clumps of differentiating blood cells |
|
|
Sinusoidal capillaries |
Leaky capillaries Feed bone marrow Oxygen and nutrients Allow blood cells to enter bloodstream to leave bone |
|
|
Erythrocyte development |
Cell volume decreases Nucleus decreases in size Chromatin condenses Nucleus is extruded from cell Number of ribosomes decreases (basophilic staining decrease) Hemoglobin levels increase (acidophilic staining increase) Organelle number drops |
|
|
Megakaryoblast |
Polyploid Nucleus (30X normal DNA) Multiple Nucleoli Highly Basophilic cytoplasm |
|
|
Megakaryocyte |
Irregular lobulation of nucleus No visible nucleoli Plasma membrane invaginates into hundreds of demarcation membranes Membrane extensions project into sinusoidal capillaries Membrane pieces are shed (4000‐8000/megakaryocyte) |
|
|
Process of granulocyte development |
Cell must develop granules First to develop is Azurophilic granules (lysosomal proteins) Second to develop are Specific granules (unique to each granulocyte type) As Specific granules develop, Azurophilic granules are less prevalent Golgi apparatus wastes away (granule production comes to an end) Nucleus becomes lobulated (cell is done dividing) |
|
|
What are the consequences of erythrocytes not having organelles? |
They depend on anaerobic metabolism of glucose They cannot make more hemoglobin They will eventually wear out (about 120 days) |
|
|
Eryptosis |
removal of dead/dying erythrocytes Occurs by macrophages in Spleen, Bone marrow and Liver Signaled through defective oligosaccharides on the RBC surface Occurs at the same rate as erythropoiesis Erythropoiesis is stimulated by Erythropoietin (EPO) from the kidney |
|
|
Important functional principles of granulocytes |
They have low protein synthesis rates They have low mitochondria – so they use glycolysis for energy High glycolysis means they can function in inflamed areas with low oxygen |
|
|
Chemotaxis |
The movement of a cell due to a chemical signal Directs leukocytes to sites of infection/inflammation |
|
|
Diapedesis |
The process of squeezing out of an intact capillary to enter the tissues Provides a way for leukocytes to access inflamed tissues Typically occurs in post‐capillary venules (low shear forces) Process is mediated by inflammatory mediators and expression of surface receptors on endothelium and leukocytes |
|
|
Neutrophils |
60‐70% of leukocytes ID characteristics: Multi‐lobed nucleus Presence of both azurophilic and specific granules, but specific granules are more prevalent Since both are present, stain appears Neutral = Neutrophil Lifespan: 6‐7 hour half‐life in the blood 1‐4 days in connective tissues Death occurs by apoptosis Functions: Phagocytosis and killing of bacteria Granules are used to kill phagocytosed bacteria |
|
|
Eosinophils |
Lifespan: 8‐12 hours in blood 8‐12 days in connective tissues Longest lasting of the granulocytes Functions: Killing of parasitic worms – large specific granules Many other less characterized functions in inflammation |
|
|
Basophils |
Lifespan: Unclear due to scarcity in blood Functions: Histamine and heparin release at inflammation sites |
|
|
Monocytes |
Lifespan: Months to years Functions: When they leave the capillary and enter tissues, they become macrophages |
|
|
Lymphocytes |
Functions: Immune cells with many functions Life span is variable (days to years) This is the ONLY leukocyte that can re‐enter the circulation |
|
|
Platelets |
Core is dense (granulomere) and contains granules Periphery is less dense (hyalomere) Open canalicular system inside the platelet connects to the outside Facilitates release of factors stored in the platelet Marginal bundle of microtubules Maintains shape of platelet Dense tubules (actin/myosin) Allows for movement of platelet during clotting |
|
|
Functions of platelets |
1. Forms a plug at site of injury 2. Releases adhesive glycoprotein and ADP 3. Releases clotting factors 4. Contraction of dense tubules – retracts clot from the vessel lumen 5. Contributes to degradation of the clot during healing |
|
|
Endocardium |
The endocardium is the inner-most aspect of the heart wall. It is composed of Endothelium, Subendotelium and subendocardium. |
|
|
Subendotelium |
- loose irregular CT - contains elastic fibers and smooth muscle cells |
|
|
Subendocardium
|
- loose irregular CT - contains elastic fibers and smooth muscle cells |
|
|
Myocardium |
iv.Cardiac muscle - arranged into layers that surround the heart chambers in a complex spiral - oriented in many directions when viewed in section - thickest in the ventricles, particularly the left ventricle |
|
|
Epicardium |
v.Adipose tissue and Loose irregular CT - coronary vessels are embedded within the adipose and CT of the epicardium. - provides support/cushioning to the heart as it beats beneath the fibrous pericardium.
vi.Visceral serous pericardium - layer of serous simple squamous mesothelium covering the visceral surface of the heart - secretes pericardial fluid into the pericardial cavity |
|
|
Four fibrous rings of the heart |
(tricuspid, mitral, aortic and pulmonary) - four rings surround the valves - dense irregular CT - provide attachment for the valve leaflets |
|
|
Two fibrous trigones |
Left and right Connect and hold the fibrous rings together |
|
|
Membranous Septa |
- dense irregular connective tissue, devoid of cardiac muscle. - branches of the conducting system (A-V bundle of His) pass through this region |
|
|
The functions of the fibrous skeleton |
- support the valves of the heart - provide attachment for the myocardium - act as an electrical insulator preventing free flow of electrical impulses between atria and ventricles. |
|
|
Fibrosa of heart valves |
- forms the core of the valve leaflet - contains dense irregular fibrous extensions of the skeletal rings of the heart. |
|
|
Spongiosa of heart valves |
- covered in endothelium - located on the atrial side (AV valves) or blood vessel side (semilunar valves). - loose and irregular in organization with numerous elastin fibers. - serves as a shock absorber that dampens vibrations associated with the closing of the valve. - confers flexibility and plasticity to the valve cusps. - aka the arterialis (in semilunar valves) - aka auricularis (in AV valves) |
|
|
Ventricularis |
- covered in endothelium - located adjacent to the ventricle. - composed of dense irregular connective tissue - in the AV valves it projects into the ventricle to form the chordae tendinea.
|
|
|
SA node |
- group of specialized cardiac muscle cells - small, thin and wavy - located at junction of the SVC and RA - initiates impulse that spreads along atrial cardiac muscle fibers and internodal tracts of modified cardiac muscle fibers. - hence the node is known as the ‘pacemaker’ |
|
|
AV node |
- impulse is picked up by AV node - group of specialized cardiac muscle cells - small, thin and wavy - located in interatrial septum near coronary sinus - delays impulse from SA node to allow emptying of atria |
|
|
AV bundle of His |
- impulse is picked up by AV bundles - group of specialized cardiac muscle cells - small, thin and wavy - located in interventricular septum - divide into left and right branches |
|
|
Purkinje fibers |
- impulse is picked up Purkinje cells - group of specialized cardiac muscle cells - larger than regular cardiac muscle cells - located in subendocardium - cause cardiac muscle of ventricles to contract at a paced interval |
|
|
Tunica intima |
The tunica intima is the inner-most lining of a blood vessel. It has three components: Endothelium, Subendothelium and internal elastic lamina |
|
|
Endothelium of the Tunica intima |
- simple squamous endothelial cells continuous with the endocardium - maintain a selectively permeable barrier - express surface adhesion molecules and receptors that allow activation of endothelial cells in response to specific environmental cues |
|
|
Responsibilities of the endothelium of the Tunica Intima |
•maintain a non-thrombogenic barrier by secreting anticoagulates (e.g. heparin) •produce prothrombogenic agents (e.g. von Willebrand factor) •modulate vascular resistance by secreting agents that promote vasoconstriction(e.g. ACE) or vasodilation (e.g. nitric oxide) •regulate angiogenesis/cell growth (e.g. TGFβ) •regulate immune responses (e.g. interleukins) •synthesize extracellular matrix proteins (e.g. Type IV, laminin in basal lamina) |
|
|
Subendothelium of Tunica intima |
loose irregular CT containing elastic fibers and, occasionally, smooth muscle cells |
|
|
Internal Elastic Lamina |
- a fenestrated sheet of elastin that permits stretch/recoil without restricting diffusion - found in vessels of the artery and arteriole size range (see later). |
|
|
Tunica media |
The tunica media is the middle layer of the vessel wall. It has two components: iv.Smooth muscle - a thick (arteries) or thin (veins) helically arranged layer of smooth muscle cells v.External elastic lamina - a second fenestrated sheet of elastin separating the t. media from the t. adventitia |
|
|
Tunica Adventitia |
The tunica adventitia is the outermost layer of the vessel wall. It has two components: vi.Dense irregular connective tissue - continuous with the fibrous layer of the pericardium at the root of the great vessels - merges circumferentially with loose connective tissue in which vessels are embedded vii.Vaso vasorum - ‘vessels of the vessel’ embedded within the t. adventitia of larger vessels viii.Nervi vascularis - ‘nerves of the vessel’ that innervate smooth muscle in the t. media |
|
|
Large elastic arteries |
The aorta is an example of an elastic artery. These vessels facilitate the movement of blood along the tube. Pressure generated by ventricular systole causes stretch of elastin fibers in the tunica media which recoils during diastole propelling the flow of blood around the circulatory system. |
|
|
Muscular artery |
Muscular arteries have more smooth muscle and less elastin in their tunica media than elastic arteries. Contraction of this smooth muscle helps maintain blood pressure. |
|
|
Arterioles |
Coordinated contraction/relaxation of the smooth muscle tunica media increases/decreases vascular resistance thereby increasing blood flow to capillary beds in areas where it is most needed (e.g. muscles during exercise or intestines after a large meal). |
|
|
Capillaries |
Capillaries are the smallest diameter blood vessels that form vascular networks allowing exchange of gases, metabolites and nutrients to move through their thin walls. The human body contains around 50,000 miles of capillaries therefore forming a huge surface area for this diffusion to occur. |
|
|
Continuous capillaries |
- found in muscle, lung and CNS - occluding junctions between endothelial cells - complete basal lamina - allow only passage of small molecules |
|
|
Fenestrated capillaries |
- found in the glomerulus of the kidney - fenestrations in the endothelial cells - complete basal lamina - allow selective filtration of molecules |
|
|
Discontinuous/Sinusoidal capillaries |
- found in liver, spleen, bone marrow - gaps between endothelial cells - incomplete basal lamina - allows free communication of blood with surrounding tissues |
|
|
Pericytes |
- contractile cells dispersed along capillaries - proliferate during angiogenesis and vascular injury to form TM of new vessels |
|
|
Metarterioles |
- initial segment of a thoroughfare channel - capillaries branching from it are surrounded by pre-capillary sphincters |
|
|
Pre-capillary sphincters |
- regulate blood flow through capillary beds - are thickened areas of smooth muscle - upon contraction, divert blood via the metarteriole through the thoroughfare channel to bypass the capillary bed. |
|
|
Venules |
A characteristic of venules is a large lumen diameter compared to the thickness of the wall. Compare these vessels with its arterial equivalent (arteriole). |
|
|
Large vein |
The tunica media is thin and adventitia is thick containing smooth muscle. The vena cava is an example of a large vein. |
|
|
Epidermis |
- is the most superficial layer of the skin - is derived from embryonic ectoderm and is a specialized stratified squamous epithelium - forms first physical and immunological barrier to invasion of foreign substances into the body. |
|
|
Dermis |
- is connective tissue derived from embryonic mesoderm - provides mechanical support and elasticity of the skin - contains immune cells involved in defense against foreign invaders passing through the epidermis |
|
|
Hypodermis |
- is connective tissue derived from embryonic mesoderm - also known as subcutaneous connective tissue - recognized as the superficial fascia in gross anatomy - stores adipose tissue for cushioning, insulation and energy. |
|
|
Name the 5 layers of the epidermis starting from most inward |
Stratum basale, Stratum spinosum, Stratum granulosum, Stratum lucidum, Stratum corneum |
|
|
Stratum basale |
- layer of columnar ‘palisades’ on the basement membrane at dermal-epidermal junction - attached to the basal lamina by hemidesmosomes and to each other by desmosomes - undergo intense mitosis and are responsible for the constant production of epidermal cells |
|
|
Stratum spinosum |
- the thickest part of the epidermis - consists of slightly flattened cells that actively synthesize keratin filaments - the filaments radiate outward and converge on the desmosomes that anchor the cells to each other |
|
|
Stratum granulosum |
- 3-5 layers of flattened cells undergoing terminal keratinization - granular appearance due to: Keratohyalin granules Lamellar bodies |
|
|
Keratohyalin granules |
Contain the protein filaggrin that binds together keratin filaments in the cytoplasm. |
|
|
Lamellar (Odland) bodies |
Contain lipid that when released by exocytosis surround the keratinocytes and prevent water loss and serve a waterproofing function. |
|
|
Stratum Corneum |
- 15-20 stacked layers of flattened non-nucleated keratinized cells filled with filamentous keratin. - continuously shed at the surface of the corneum |
|
|
Melanocytes |
- neural crest derived cells that have migrated into the stratum basale of the epidermis - have characteristically long, irregular processes that branch into the epidermis between the keratinocytes of the stratum basale and spinosum - one melanocyte serves 5-6 basal keratinocytes forming a epidermal-melanin unit |
|
|
Pigmentation and melanin |
- primarily responsible for skin color - synthesized by melanocytes and accumulates in vesicles called melanosomes - transported within melansomes to the end of melanocyte processes. - phagocytosed when keratinocytes phagocytose the melansome containing processes - is released from melansomes around the keratinocyte nuclei. - absorbs and scatters sunlight to protect nuclear DNA from UV radiation. |
|
|
Merkel Cells |
Merkel cells are mechano-receptors derived from neural crest cells and located in the stratum basale. They are present in greatest numbers in areas of high tactile sensitivity. Their basolateral surfaces contact sensory nerve fibers that penetrate the basal lamina. |
|
|
Langerhans cells |
Langerhans cells are antigen-presenting cells. They are found in the stratum spinosum but send out long processes between the keratinocytes of all layers. Due to this extensive coverage of the skin, they can present any antigens that may invade the epidermis to surrounding T-lymphocytes triggering an immune response. |
|
|
Dermis |
The dermis is the connective tissue component of the skin. It supports the epidermis and binds it to the hypodermis and contains the numerous blood vessels that supply the avascular epidermis with nutrients and are responsible for thermoregulation. Some things seen in the dermis are: Papillary dermis, reticular dermis, dermal papillae, Vascular network and meissner's corpuscles |
|
|
Dermal papillae |
- a series of dermal projections into the epidermis - more pronounced in regions of skin that regularly receive pressure (soles, hands etc). |
|
|
Papillary dermis |
- a thin layer of loose irregular connective tissue below the basement membrane - it forms the dermal papillase - anchoring fibrils (Type VII collagen) in this layer insert into the basal lamina to hold the epidermis and dermis together. |
|
|
Reticular dermis |
- a thick layer of dense irregular connective tissue immediately below the papillary dermis. - contains Type I collagen bundles which gives skin its strength against tensile forces - contains elastin fibers (seen only with special stains) that provide skin with its elasticity. - contains glands and hair follicles (see adnexa). |
