Foundations of medicine Block 1 Week 3 Flashcards
How much water is in the lungs, muscles, fat and bones ?
Lungs - 84% water (4% of body mass)
Muscle - 79% water (32% of body mass)
Fat - 50% water (14% of body mass)
Bone - 32% water
How much water is in the lungs, muscles, fat and bones ?
Lungs - 84% water (4% of body mass)
Muscle - 79% water (32% of body mass)
Fat - 50% water (14% of body mass)
Bone - 32% water (15% of body mass)
There is more water in lean muscle than there is in fatty tissue.
How much fluid does a baby, male (adult), female (adult) or old person have in their body ?
baby - 75% fluid because they have low bone and fat mass
Male adult - 60% fluid ( males generally have more muscle mass)
female adult - 50 - 55% fluid
Old person - 45 % fluid because they have less muscle mass and the ability to hold water.
What equation is used to find out how much fluid is in the body ?
Total body fluid = 60% x Body Weight (kg)
What is the composition of body fluid ?
2/3 (63%) of body fluid is intracellular fluid
1/3 (37%) of body fluid is extracellular body fluid.
The extracellular fluid is split into:
Interstitial fluid
Plasma
Lymph
Transcellular fluid
Intracellular: inside cells
Extracellular: outside cells. Includes interstitial fluid.
Interstitial fluid : The interstitial fluid is the fluid that fills the spaces between cells. It is composed of water, amino acids, sugars, fatty acids, coenzymes, hormones, neurotransmitters, salts, and cellular products. Its main function is to bathe and surround the cells of the body.
Transcellular fluid - found in cavities
Cerebrospinal fluid - Cerebrospinal fluid is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialized ependymal cells.
Synovial fluid - found in synovic joints
Serous fluids:
Pericardial fluid (heart)
Pleural fluid (lung)
Peritoneal fluid (is a serous fluid made by the peritoneum in the abdominal cavity which lubricates the surface of tissue that lines the abdominal wall and pelvic cavity)
Intraocular fluid - fluid in eyeball. Too much fluid in the eyeball can cause GLAUCOMA.
How much blood can you donate ?
Total blood volume = 8% x Body weight (kg)
What criteria do the hospital check before taking your blood ?
Check you weigh over 50kg (7stones).
age between 17 and 66.
If you are 70 you need to have given blood in the last 2 years to continue donating.
50kg - has 10 pints of blood. The hospital takes 1 pint. Which is 10% of blood.
If your less like 45kg - you have less blood. so a 1 pint donation would be too much. It would be 16% of your blood.
Hospital will not take more than 10% of a patients blood.
And they wont take less than a pint because it doesn’t help
What is the composition of body fluids ?
Mainly water (solvent)
and
Non electrolytes and electrolytes (solutes).
Non electrolytes:
do not dissociate in water ( covalent bond)
No electric charge
Examples: lipids, glucose, urea
Electrolytes:
Dissociate into ions (non covalent bond)
Electric charged
Examples: salts, acids, bases and proteins
Composition of electrolytes in body fluid
How much electrolytes are inside (intracellular) and outside the cell (extracellular) ?
Varies depending on the ion.
We have a lot of sodium in the extracellular space
We have a lot of potassium in the intracellular space
Na+ and K+ compositions in the blood.
What happens when you centrifuge red blood cells ?
When you centrifuge blood the top layer is always plasma.
The middle layer is the buffy coat
And the bottom layer is erythrocytes.
Blood clotting factors ?
White blood cells in blood ?
What is homeostasis ?
Homeostasis is the body’s ability to regulate its internal environment and maintain constant conditions of properties like temperature and pH.
What is the Maintenace of ECF ?
The maintenance of the ECF as a steady state
What is intravascular fluid ?
Part of the extracellular fluid.
Intravascular fluid is whole blood volume and also includes red blood cells, white blood cells, plasma, and platelets. Intravascular fluid is the most important component of the body’s overall fluid balance.
What is the relationship between interstitial fluid and intravascular fluid ?
Another word for intravascular fluid is blood plasma
Interstitial fluid and intravascular fluid are at equilibrium.
There are endothelial cells between interstitial and intravascular fluid.
These endothelial cells are leaky, there is no barrier to the movement
How is blood exchanged between blood plasma and Interstitial fluid ?
- Hydrostatic pressure - Filtration
Pressure exerted by blood on capillary walls.
Around daily 20L of fluid is filtered out daily. - Osmotic pressure - Reabsorption
“negative” pressure created by proteins in the blood ( Albumin ) > fluid renters the blood.
What is the difference between arteries and veins ?
Types of blood vessels ?
- Continuous capillary
- Fenestrated capillary
- Sinusoid capillary
What is Hydrostatic Pressure (HP) ?
What opposes Hydrostatic Pressure ?
Capillary hydrostatic pressure: The force of hydrostatic pressure means that as blood moves along the capillary, fluid (blood plasma) moves out through its pores and into the interstitial space. Around 20 liters of fluid is filtered out daily.
Hydrostatic pressure facilitates filtration.
The opposing force is interstitial fluid hydrostatic pressure, this does not pull fluid into the capillary it just hinders fluid leaving
The capillary hydrostatic pressure is the greater force compared to interstitial fluid hydrostatic pressure.
We need more blood plasma to leave capillaries so that our tissues get more nutrients.
What is Plasma Osmotic Pressure (OP) ?
Plasma is going to move from areas of low osmotic pressure to high osmotic pressure. At the distal end of the capillary at the venule end there will be a very high concentration of the protein (e.g. Albumin) compared to our interstitial fluid (extracellular space). Therefore fluid will flow from the interstitial fluid back into the capillary.
So Plasma osmotic pressure causes reabsorption. Fluid (blood plasma ) reenters the capillary.
What exchange happens between the interstitial fluid and different organs ?
Histological image of artery and veins?
Lumen of vein is much bigger than that of a artery
Arteries have a bigger layer of smooth muscle cells compared to veins
Arteries have elastic membrane and veins do not.
Arteries have no valves and veins do
Why is the lymphatic system important ?
Fluid is drainage into the lymphatic system then returned via the venous system back to the heart.
Lymph nodes have lymphocytes which are a types of white blood cells and that includes B cells and T cells.
Lymphatic system functions:
- Transports clean fluids back to the blood
- Drains excess fluids from tissues
- Removes “ debris” from cells of the body
- Transports fats from the digestive system.
What is a lacteal ?
Is the lymphatic vessels of the small intestine which absorb digested fats.
The 3 main vessels of the villi of the small intestine are the vein, artery and lacteal.
Lacteals are a type of lymphatic capillary which acts to absorb dietary fat in the small intestine. Lacteals drain into larger and larger lymphatic vessels until the fat has made it back into the circulatory system.
What are lymph nodes ?
Lymph nodes are filled with immune cells known as lymphocytes. These lymph nodes check the lymph and if they encounter a bacterium their trigger an immune response. They make sure no bacteria is trying to take root in the very slow moving lymph.
During an infection your lymph nodes may swell up and become tender and painful.
The lymph eventually reaches the circulatory system and replaces all the blood plasma (fluid) which was lost in the capillaries.
Lymphatic vessels deliver the lymph to 2 circulatory veins.
Right lymphatic duct bring lymph from the right upper half of the body, this is drained into the right subclavian vein.
The majority of the body’s lymph is delivered by the thoracic duct and drains into the left subclavian vein.
Types of blood vessels ?
The endothelial cells that line the capillaries are different (some are more leaky whereas others are less) they determine fluid movement.
Continuous capillaries - are the least permeable. They are found in skin and muscle.
Fenestrated capillaries - Fenestrations (pores) are more porous. They are found in kidneys and small intestine. Kidneys need to filtrate the blood.
Sinusoid capillary - most permeable. Found in bone marrow , liver and spleen.
How is fluid exchanged between the Extracellular fluid and Intracellualr fluid ?
The exchange of materials between intracellular fluid and extracellular fluid occurs between the cell membrane.
Energy is required to exchange substances between extracellular fluid and intracellular fluid. The energy drives ion pumps.
The concentration of substances inside (intracellular) and outside (extracellular) the cell have to be relatively constant, they cant change too much.
What is found more in intracellular fluid is : K, Mg and P
What is found more in extracellualr fluid is
What is permeable across the cell membrane ?
What is Osmolality?
Is a unit Osm/kg
It is the concentration of solutes per litre.
If a solute like salt breaks up in water it increases the amount of solute in the water.
What is the distribution of electrolytes intercellularly and extracellularly ?
Extracellular fluid (interstitial fluid and blood plasma ) is made up of mainly: Na+
Cl-
HCO3-
Intracellular fluid:
K+
Mg+
Organic Phosphates
Describe isotonic cells ?
Describe Hypertonic cells ?
Describe Hypotonic cells ?
Isotonic - the extracellular fluid has the same osmolality as the cell. No net movement of water in or out of cell.
Hypertonic: The extracellular fluid has a higher concentration of solutes (high osmolality) than cell cytoplasm. So water moves out of the cell.
Hypotonic solution: extracellular fluid has a lower concentration of solutes than fluid inside the cell. So water enters the cells.
What happens when you eat too much salty food?
Where is the salt added when you eat more salt ?
Does the sodium concentration in the body change ?
- When you eat too much salty food you drink more water. As you drink water the water will equalize the increase in Na+ concentration.
- The sodium is added to the Extracellular fluid
- No. You balance it out by getting rid of it in your urine.
What is Oedema ?
Odema occurs when the amount of fluid in the interstitial space increases or fails to be removed. This may be caused by an event that steps up the amount of fluid coming out of the blood or hinders its return
The fluid is present in the interstitial tissue and not the cell.
What are the factors that cause Odema ?
What is Elephantiasis ?
What are the 5 infectious agents ?
- Viruses
- Bacteria
- Fungi
- Protozoa
- Helminths ( cestodes, trematodes, nematodes).
What do the following terms mean:
Commensalism
Mutualism
Parasitism
Commensalism: an association between two organisms in which one benefits and the other derives neither benefit nor harm.
Mutualism: Mutualism is a type of symbiotic relationship where all species involved benefit from their interactions. Both organisms benefit.
Parasitism: Parasitism is a nonmutual relationship between two organisms in which one benefits at the expense of the other. There are two types of parasites affecting living organisms: ectoparasites (living on the surface of host) and endoparasites (living in the body of host).
What is an antigen ?
Define viruses ?
Shape of viruses ?
How to viruses replicate ?
