Mix Flashcards
Name two important substances produced from intermediates of glycolysis and their roles
Glycerol phosphate made from 3C dihydroxyacetone in adipose tissue= needed for the synthesis of triglycerides
2,3 bisphosphoglycerate made from 1,3 bisphosphoglycerate in RBCs= regulator of oxygen affinity of haemoglobin
Main functions of connective tissue
Connection: join together other tissues
Support the body and its structures
Protection for underlying organs
Where does areolar connective tissue occur widely?
Superficial fascia aka subcutaneous tissue: general coating of body beneath the skin
- face or dorsum of the hand
What is deep (investing) fascia?
Dense CT mostly associated with muscles, bones, nerves and blood vessels
What is adipose tissue composed of and what is its function?
Fat cells
acts as energy reserve
thermal insulator
mechanical shock absorber
What are the three types of dense regular connective tissue and what do they consist of?
Tendon: a cylindrical mass of connective tissue
Ligament: parallel arranges of collagen fibres
Aponeurosis: tendon flattened into a thin board sheath
What causes Marfan’s syndrome?
Mutations in the fibrillin gene whose protein
product binds to and supports the function of elastin.
Loss of fibrillin protein,
results in disorders of elastin function leading to tissue irregularities such as long bones, lax joints and fragile vascular walls
What causes Scurvy?
Vitamin C deficiency
results in the synthesis of abnormal collagen
that lacks its usual strength; it is also associated with an inability to heal
wounds and bone fractures.
What are the defence cells in connective tissue?
Macrophages
Mast Cells
Plasma cells
Blood cells (blood is considered to be a specialised connective tissue that ‘communicates’ throughout the body and so communicates the
actions of one tissue on another, e.g. the hormonal control exerted by the hypothalamus and pituitary on a number of end endocrine
glands.)
Examples of Loose connective tissue
subcutaneous tissue, the septa and trabeculae that make up the framework inside some organ adipose tissue Blood
What does the dermis consist of?
Lies below the epidermis
Consists of a thick layer of connective tissue containing blood vessels, lymphatics, skin
appendages (e.g. hair follicles, sebaceous glands and sweat glands), sensory
nerves and nerve endings.
consists of bundles of collagenous fibres running in various directions. There are also variable amounts of elastic fibre which form a network between the collagenous bundles.
Fascicles are formed from
Groups of collagenous
fibres and fibroblasts
What separates fascicles from each other?
loose connective tissue, called endotendineum
Where is loose connective tissue first seen?
in the developing embryo as mesenchyme, consisting of mesenchymal cells surrounded by a relatively fluid intercellular substance. With time in utero, IC substance becomes more mucoid
What is mucous connective tissue called in the umbilical cord?
Wharton’s jelly: oose, amorphous connective
tissue with a jelly-like matrix composed mainly of hyaluronic acid, sparsely populated with
type I and III collagen fibres and fibroblasts.
Describe the properties of amphipathic molecules and explain the progress of formation of lipid bilayers
Amphipathic molecules- hydrophillic and hydrophobic moieties
= form micelles (circle) and bilayers in water
Bilayer formation is spontaneous in water driven by VDW attractive forces between hydrophobic tails
Stabilised by non-covalent forces; electrostatic and hydrogen bonding between hydrophillic moieties and interactions between hydrophillic groups and water
Low permeability to ions and most polar molecules
Describe the features of integral proteins which explains their topology in the membrane
Most integral proteins contain residues with hydrophobic side chains that interact with fatty acyl groups of the membrane phospholipids, thus anchoring the protein to the membrane
What is membrane asymmetry?
when the inner and outer leaflet have different molecular architecture
Discuss the influence of unsaturated fatty acids and cholesterol on membrane fluidity
When compressed: unsaturated fatty acids= the “kinks” in their tails
-elbow adjacent phospholipid molecules away= maintaining some space between the phospholipid molecules.
Helps to maintain fluidity in the membrane at temperatures at which membranes with saturated fatty acid tails in their phospholipids would “freeze” or solidify.
cholesterol functions as a buffer, preventing lower temperatures from inhibiting fluidity and preventing higher temperatures from increasing fluidity too much
Describe the main features of fluid mosaic model of membrane structure
Plasma membrane as a fluid combination of phospholipids, cholesterol, and proteins. Carbohydrates attached to lipids (glycolipids) and to proteins (glycoproteins) extend from the outward-facing surface of the membrane.
Explain the restrictions on protein movement in the membrane, including potential interactions with cytoskeleton elements
Lipid mediated effects: proteins tend to separate out into the fluid phase or cholesterol poor regions
Membrane protein associations
Association with extra-membranous proteins via cytoskeletons
What are the two types of sphingolipid?
Sphinogomyelin
Conformation resembles other phospholipids in membrane
Can be a glycolipid if phosphocholine is replaced with sugar
Glycolipd
Cerebrosides- head group sugar monomers
Gangliosides head group oligosacchide
How does cholesterol contribute to membrane stability?
Cholesterol is 45% of total membrane lipid
Polar head group
Rigid planar steroid ring structure
Non-polar hydrocarbon tail
= reduces phospholipid packing = increased fluidity
What are the dynamics in lipid bilayers
Fluid structures.
Lipid molecules posses four permitted modes of mobility:
1. Intra-chain motion- kink formation in fatty acrylic chains
2. Fast axial rotation
3. Fast lateral diffusion within the plane of the bilayer
4. Flip-flop- movement of lipid molecules from one half of the bilayer to the other
What are some distinctive functions of membrane proteins?
Enzymes Transporters Pumps Ion channels Receptors Energy transducers
How are peripheral membrane proteins associated with the surface?
By electrostatic and hydrogen bond interactions
Removed by changes in pH or ionic strength.
What is spectrin?
Spectrin Is a Cytoskeletal Protein Noncovalently Associated with the Cytosolic Side of the Red Blood Cell Membrane.
Binding of spectrin depends on a large intracellular attachment protein called ankyrin, which attaches both to spectrin and to the cytosolic domain of the transmembrane protein band 3
Examples of long bones
The major bones of the upper limb (humerus, radius, and ulna) and the lower limbs (the femur, tibia, and fibula) are all long bones
What is bone marrow?
Bone marrow is a semi-solid tissue found within the spongy or cancellous portions of bones and is the primary site of new blood cell production (haemopoiesis).
What is bone marrow composed of?
It is composed of hematopoietic cells, marrow adipose tissue (fat), and supportive stromal cells.
Where is bone marrow found in adults?
In adult humans, bone marrow is primarily located in the ribs, vertebrae, sternum, and bones of the pelvis
How does bone marrow red blood cells join the systemic circulation?
permeable vasculature sinusoids within the medullary cavity
what two parts form blood?
formed elements (i.e. blood cells and platelets) and a liquid phase called plasma
What are the two types of blood corpuscles?
the red blood corpuscles (erythrocytes) and the white blood corpuscles (leukocytes)
leukocytes are further classified into…
polymorphonuclear granulocytes (cells whose nuclei are lobed and whose cytoplasm is filled with granules)
mononuclear cells or agranulocytes (cells having a normal looking nucleus and cytoplasm free of granules).
Name three polymorphonuclear granulocytes
Neutrophils
Eosinophils
Basophils
Neutrophil: function and structure
most numerous of the granulocytes
pale cytoplasm containing very fine indistinct granules
phagotic= granules are actually lysosomes containing digestive enzymes
short-lived= become pus cells (gross accumulations of cells in pus)
Migrate through walls of blood vessels to reach sites
Eosinophils: function and structure
cytoplasm that is completely filled with large granules which stain red
highly mobile
weakly phagocytic
ingest antigen-antibody complexes
abnormally high concentrations in allergic conditions
Basophils: function and structure
least common of all the cells found in blood
granules stain intensely blue
granules contain heparin, serotonin and histamine
resemble mast cells
How doe basophils contribute to parts of the inflammatory responses and after local tissue damage?
basophil granules are released into the tissue at the site of the injury. The histamine causes vasodilation and leakage of fluid into the tissues (oedema) and the heparin prevents clotting of the blood
What is another name for agranulocytes?
mononuclear cells
Name two types of agranulocytes are found in the circulating blood
monocytes and lymphocytes
Monocytes: function and structure
actively phagocytic and motile
largest cells in the peripheral blood
the nucleus is usually irregular in shape: often kidney-shaped
Lysosomes are present in the cytoplasm but are barely visible with the light microscope
What are histiocytes and what is their function?
tissue macrophages
mononcytes that have passed through the walls of the smallest blood vessels into the surrounding tissue.
Involved in phagocytosis as part of the immune response. monocytes may return to the circulation when the immune response subsides
Lymphoctyes: function and structure
very high nuclear to cytoplasmic ratio with a thin rim of cytoplasm evident around the nucleus
nuclear chromatin stains darkly and usually has a clumped appearance.
Small lymphocytes are actively mobile cells
fundamental part of the adaptive immune response to foreign materials
Platelets: function and structure
smallest cells in the blood
non-nucleated and tend to occur in groups
rich in compounds that cause constriction of blood vessel walls
rich in phospholipid Factor III
function: to assist in the clotting (coagulation or thrombosis) of blood
Why are platelets rich in phospholipid Factor III>
phospholipid Factor III activates prothrombin into thrombin; the latter converts soluble fibrinogen into insoluble fibrin to form the blood clot.
What does blood plasma constitute of?
a large number of substances:
Proteins (e.g albumins, globulins, fibrinogen)
Mineral ions
Minute fat globules( chylomicrons)
small particles of broken down blood corpuscles
All dissolved in water which constitutes ~90% of total volume of plasma
Name the two types of artery
elastic and muscular
What doe arterioles have a major role in?
the control of blood flow to specific regions of the body (brain, heart, kidneys, etc.) and in the control of central (arterial) blood pressure
Name the key (conducting) arteries and their main function?
Aorta brachiocephalic truck Carotid arteries Subclavian arteries Iliac arteries Pulmonary arteries =transport blood away from the heart towards medium sized arteries called distributing arteries
Where do the key arteries supply blood?
Aorta Brachiocephalic trunk (supplying the head, neck and upper limbs) Carotid arteries (supplying the head and neck) Subclavian arteries (supplying the upper limbs) Iliac arteries (supplying the lower limbs) Pulmonary arteries (that contain deoxygenated blood from the right ventricle of the heart) carry blood to capillaries that lie adjacent to alveoli in the lungs and thus allow efficient gaseous exchange.
Examples of muscular arteries
radial and femoral arteries of the upper and lower limbs, respectively.
Why are the largest arteries elastic arteries?
they contain large numbers of collagen and elastin fibres in their walls, which give the arteries the ability to stretch in response to each pulse of blood as it progresses through the vessel, and then return to their original size
