Cardio Flashcards
What is the pericardium?
Outermost layer of the heart
Layer of mesothelial cells resting on thin layer fibrous connective tissue
Visceral and parietal
What is the epicardium like?
Sometimes used interchangeably with pericardium
Strictly it is the underlying adipose connective tissue, vessels and nerves
Between pericardium and myocardium
What is myocardium like?
Thickest layer of the heart
Specialised cardiac muscle
Striated
Central nuclei
Branching
Intercalated discs
What are intercalated discs like?
Connect adjacent cardiac myocytes
Contain:
Gap junctions
Adhering junctions
Desmosomes
What is endomysium like?
Loose fibrous connective tissue between the muscle fibres (endomysium)
What does myocardium like?
Atrial myocytes are small than those in the ventricles
Contain perinuclear neuroendocrine granules (atrial natriuretic peptide)
The heart is an endocrine organ!
What is in the conducting system?
Sinoatrial node
Atrioventricular node
Bundle of His
Purkinje fibres
Subendocardial
Large vacuolated muscle cells
What is the endocardium composed of?
Innermost layer of heart
Thin layer of fibrous connective tissue
Endothelial cells
What are valves like?
Covered by endothelium
Attach to central fibrous body
Endothelial cells on either side
Fibrosa (dense fibrous CT)
Spongiosa (loose fibrous CT)
Ventricularis (collagen & elastin)
Interstitial cells inside like smooth muscle cells, fibroblasts and myofibroblasts
What are the layers of the heart?
Pericardium
Epicardium
Myocardium
Endocardium
What does myocardium comprise?
Myocardium comprises a specialised form of involuntary striated muscle known as cardiac muscle
What are valves?
Valves are specialised extensions of endocardium
What is plasma?
Plasma is blood minus the cells and comprises:
water
salts & minerals
plasma proteins (albumins, globulins, fibrinogen)
hormones, signal molecules
other clotting factors etc.
What is serum?
Serum is plasma minus clotting factors
What are erythrocytes like?
4-6million per mL blood
Lifespan of 4 months
Produces in liver (fetus) and bone marrow
Enucleate, biconcave discs - 6/5-8.5 micrometer in diameter (end to end about 180km)
Major protein is haemoglobin
Destroyed in the liver and spleen
Cell membrane has important endoskeleton attached (major protein -spectrin)
What are the white cell series (leucocytes)?
Granulocytes (contain visible granules)
40-75% Neutrophils
~ 5% Eosinophils
~ 0.5% Basophils
Agranulocytes (no visible granules)
20-50% Lymphocytes
1-5% Monocytes
Platelets (cell fragments)
What are neutrophils?
- Polymorphonuclear leucocytes
Commonest WBC
Commonest granulocyte
Multi-lobed nucleus, granular cytoplasm (12-14micrometer) in diameter
Phagocytic - engulf and destroy bacteria and other foreign macromolecules
Circulate in blood and invade tissue spaces
Contain myeloperoxidase
What does neutrophils contain?
Polymorphonuclear leucocytes
Contains 3 types of cytoplasmic granule
Primary granules
Lyzosomes - myeloperoxidase acid hydrolases
Secondary granules
Specific granules - secrete substances that mobilizer inflammatory mediators
Tertiary granules
Gelatinases and adhesion molecules
What are eosinophils?
1% of total number of white cells
Numbers increase in parasitic infections
12-17 μm in diameter
Bi-lobed nucleus
Distinctive large red cytoplasmic granules with crystalline inclusions
Antagonistic in action to basophils
What do eosinophils do?
Characteristic lozenge-shaped granules with crystalline cores
Phagocytic with particular affinity for antigen/ antibody complexes
Receptors for IgE
Inhibit Mast cell secretion
Neutralise histamine – thereby restricting inflammatory responses
What are basophils?
0.5% of white cell series,
14-16 μm in diameter
Bi-lobed nucleus and prominent dark blue-staining cytoplasmic granules
Granules contain histamine.
Involved in inflammatory reactions and act to prevent coagulation and agglutination
What do basophils do?
Circulating form of the tissue Mast Cell
Receptors for IgE
Release histamine and other vaso-active agents in response to allergens
Results in immediate hypersensitivity reaction
What are they two functional subtypes of lymphocytes?
Two functional subtypes
B Cells - become plasma cells and secrete antibodies
T Cells - are involved in cell-mediated immunity
Very few cytoplasmic inclusions and hence have a clear blue/grey cytoplasm
What are they two functional subtypes of lymphocytes?
Two functional subtypes
B Cells - become plasma cells and secrete antibodies
T Cells - are involved in cell-mediated immunity
Very few cytoplasmic inclusions and hence have a clear blue/grey cytoplasm
What are the cells of lymphocytes?
B Cells – produce antibodies
T Helper (TH) Cells – help B cells and activate macrophages
T Cytotoxic (TC) Cells – kill previously marked target cells
T Suppressor (TS) Cells – suppress TH cells and hence suppress the immune response
Natural Killer (NK) Cells – mainly kill virus infected cells
ALL look the same in histological sections on
H+E
What are monocytes?
Immature cells, circulate briefly in blood
Characteristic reniform nucleus
15-20 μm in diameter
Differentiate into one of several cell types within tissue
Major phagocytic and defensive role
Some become antigen presenting cells, passing antigen fragments to lymphocytes
What do monocytes differentiate into?
Small cytoplasmic granules (despite
classification!), mostly lysosomes
Differentiate into
Tissue macrophages - everywhere
Kupffer cells – liver
Osteoclasts – bone
Antigen presenting cells - everywhere
Alveolar macrophages – lung
What are platelets?
Fragments of cells derived from large multi-nucleated Megakaryocytes in the bone marrow
1 to 3 μm in diameter, surrounded by cell membrane and containing vesicles with coagulation factors
Responsible for clotting of blood, notably when the endothelium lining all blood vessels is breached
What occurs in hematopoiesis?
All blood cells form in the haematopoeitic bone marrow in adults (liver in the fetus)
Myelon series lies next to bone and gives rise to white blood cells
Erythron series lies in between bony trabeculae and gives rise to erythrocytes
Megakaryocytes lie in between bony trabeculae and give rise to platelets
What is erythropoeisis?
Reducing cell size
•Haemoglobin production
•Reduction and loss of organelles
•Basophilia in early precursors changes to eosinophilia in late precursors
•Loss of nucleus
•Mediated by erythropoeitin (EPO)
What is granulopoeisis?
Morphology similar for neutrophils, eosinophils and basophils
•Increasing number of granules
•Increasingly complex shape of the nucleus
•Large pool of stored mature neutrophils in marrow
Where are blood cells formed?
Blood cells are formed in haematopoeitic bone marrow, ultimately from a single precursor
What occurs in the formation of blood cells
There are multiple precursors in the formation of blood cells. You are not expected to be able to identify the precursor cells, but you should know where different elements of haematopoiesis occur.
What is the most common cell and leucocyte?
Erythrocytes most common cell
•Neutrophils most common leucocyte
What if imp to remember?
Function dictates form! For:
Filtration
Humidification
Warming
Olfaction (and taste)
Gas transport
Speech
Protection against infection
Gas exchange
What is respiratory epithelium like?
Lines the tubular portion of the respiratory
Pseudostratified - all cells contact b.m
Ciliates epithelial cells
Interspersed goblet cells
What occurs in the noses?
Filtration
Humidification
Warming
Olfaction
What is found in the nose?
Keratinising and non-keratinising squamous epithelium
Respiratory epithelium
Richly vascular laminated proprietary containing seromucinous glands
What is found in the nose?
Keratinising and non-keratinising squamous epithelium
Respiratory epithelium
Richly vascular laminated proprietary containing seromucinous glands
What occurs in olfaction?
Roof of the nasal cavity, extending down septum and lateral wall
Pseudostratified columnar epithelium of olfactory receptor cells with supporting sustentacular cells and basal cells
Serous glands of Bowman
What cells are found in olfaction?
Olfactory receptor cells - Bipolar neurons – dendrite extends to surface to become club-shaped ciliated olfactory vesicle
What occurs at the nasopharynx?
Gas transport
Humidification
Warming
Olfaction
Lined by Resp epithelium
What are the nasal sinuses?
Frontal
Ethmoid
Maxillary
What do nasal sinuses do?
Lower the weight of the skull
Add resonance to the voice
Humidify and warm inspired air
Lined by respiratory epithelium
What is the larynx like?
Cartilaginous box
Voice production
Respiratory epithelium
Loose fibrocollagenous stroma with seromucinous glands
Lymphatics and blood vessels common
What are the vocal cords like?
Voice production
Stratified squamous epithelium overlying loose irregular fibrous tissue (Reinke’s space)
Almost no lymphatics
What is the trachea like?
Conducts air into and from the lungs
Respiratory epithelium
Seromucinous glands in submucosa
Tracheal is muscle posteriorly
C-shaped cartilaginous rings
What is teh composition of bronchi and bronchioles?
Main bronchi -> lobar bronchi -> segmental bronchi -> bronchioles
Smooth muscle
Partial cartilaginous rings
Respiratory epithelium
Ciliates columnar epithelium
Some basal neuroendocrine cells
Seromucinous glands and goblet cells
Few goblet cells
Clara cells
Order? Which is which!!!1
What ate Clara cells?
Most numerous in terminal bronchioles, Mitochondria, Smooth ER, Secretory granules
No cilia; vesicular cytoplasm
Precise function uncertain… but believed:
Oxidise inhaled toxins?
Antiprotease function?
Surfactant production / elimination?
Stem cell?
??
What are respiratory bronchioles like?
First part of distal respiratory tract
Gas exchange as well as transport
Link terminal bronchioles and alveolar ducts
Cuboidal ciliated epithelium
Spirally-arranged smooth muscle
What is alveoli?
150-400 million/lung
250 µm in diameter
GAS EXCHANGE
What are teh types of alveoli?
Type 1 pneumocytes
40% cell population
90% SA
Flattened cells, flattened nucleus, few organelles
Type 2 pneumocytes
60% cell population
5-10% SA
Rounded cells, round nucleus, rich in mitochondria, smooth and rough ER, spherical bodies
Produce surfactant
What are alveolar macrophages?
Alveoli – cell types
Alveolar macrophages
Luminal cells, also present in the interstitium
Phagocytose particulates including dusts and bacteria
Enter lymphatics or leave via mucociliary escalator
What is the BBB like?
blood-air barrier
Type 1 pneumocyte
Fused basement membrane of pneumocyte and capillary
Vascular endothelial cell
200-800nm thick!
How linked to alveoli?
What is the interstitium of the alveoli?
Where endothelial cells are not in direct contact with
Pneumocytes
Collagen and elastin fibres
Fibroblasts
Macrophages
(Pores of Kohn)
What is the visceral pleura like?
visceral pleura
Flat mesothelial cells
Loose fibrocollagenous connective tissue
Irregular external elastic layer
Interstitial fibrocollagenous layer
Irregular internal elastic layer
What are the conducting parts of the airways lined by?
Ciliated epithelium which becomes flatter more distally
What are the walls for alveoli like?
The alveoli - very thin walls
What does alveolar interstitium contain?
Blood vessels, lymphatics, collagen and elastin and some macrophages
