5: Organ Systems Flashcards
What is the integument system?
The term integument system is used to describe the skin and its associated structures. Eg: hair, nails, glands
It’s the largest organ of the body
What is the role of the integument system?
The role of the integument system is to form a boundary between our internal and external environment. It prevents death by infection, water loss and heat loss
It’s major roles are: protection, temperature regulation, sensory perception, metabolism and waste disposal
Explain the integument system’s role of protection:
The integument system separates internal and external environments and protects the body in three main ways:
- Physical barrier
- Chemical barrier
- Biological barrier
How does the integument system work as a physical barrier?
The integument works as a physical barrier because the protein keratin in the skin’s surface and the skin cell’s secretions makes skin waterproof. Connective tissues make it durable and flexible
How does the integument system work as a chemical barrier?
The integument works as a chemical barrier because skin secretions are acidic and antibacterial so retard bacteria growth. Melanin in skin cells shields from UV radiation
How does the integument system work as a biological barrier?
The integument system works as a biological barrier because cells of the immune system live within the skin. They recognise foreign bodies and organisms (called antigens) that are invading and destroy them. This helps in the destruction of viruses and bacterias
Explain the integument system’s role as a temperature regulator:
The skin is an integral component of the homeostatic mechanisms that monitor and regulate the body’s temperature so that it can work most effectively within its narrow temperature range
Explain the integument system’s role in sensory interaction with the environment:
The skin contains sensory receptors that respond to light touch, deep pressure, displacement of the hair shaft and free nerve endings that detect temperature changes and excessive forces that cause pain
Explain the integument system’s role in metabolic functions:
Sunlight acts on modified cholesterol molecules in the dermal blood vessels. This converts them into vitamin D to be used elsewhere in the body
Explain the integument system’s role in excretion:
The integument system eliminates nitrogen containing wastes from the body in the form of sweat, which also loses water and salts, which have to be replaced by dietary intake
What is the structure of the skin?
The skin is pliable, tough, stretchable, waterproof and self-repairing. It is made up of keratinised stratified squamous epithelium
The skin has two main layers: the outer epidermis and inner dermis, with the hypodermis beneath
Within the body’s orifices, the skin is un-keratinised
What is the structure of the epidermis?
The epidermis is mainly keratinised stratified epithelium. Over most parts of the body is thin skin, which has four layers. On the fingertips, palms and soles of the feet there is an extra layer
The non-keratinised skin is more uniform, with surface layers still alive (unlike keratinised epidermis). This is found in specialised tissues and is kept from drying out by a variety of secretions
What are the layers of thin skin?
The layers within thin skin are:
- Stratum corneum
- Stratum granulosum
- Stratum spinosum
- Stratum basale
What are the layers of thick skin?
Thick skin has the same four layers as thin skin: 1. Stratum corneum 2. Stratum granulosum 3. Stratum spinosum 4. Stratum basale PLUS 5. Stratum lucidum
What are the cell types and their roles in the epidermis?
The four cell types in the epidermis are:
- Keratinocytes (the majority type)
- Melanocytes (skin pigmentation)
- Merkel cells (skin sensation)
- Langerhans’ cells (immune cells)
What is the structure of dermis?
Dermis is the innermost component of the skin and is tough and leathery
It is made of dense irregular connective tissue and is strong and flexible
What are the components of the integument within the dermis?
There are 5 components of the integument within the dermis:
- Blood vessels
- Nerves
- Sweat glands
- Sebaceous glands
- Hair
What are the roles of nerves within the dermis?
Within the dermis, nerves are used for sensory and motor activities
What are the roles of sweat glands within the dermis?
Sweat glands can be eccrine glands (sweat first) and apocrine glands (begin to excrete from puberty)
What are the roles of sebaceous glands within the dermis?
Within the dermis, sebaceous glands secrete an bactericidal oil called sebum to soften and lubricate the hair and slow water loss from the skin
Sebaceous glands are simple alveolar glands regulated by hormones
What is the role of hair within the dermis?
Within the dermis, hair is produced by follicles that extend from the epidermal surface deep into the dermis
What is the definition of the digestive system?
Th digestive system is a number of structures that carry out the tasks involved in gaining nutrients. AKA gastrointestinal system
What is the role of the digestive system?
The digestive system carries out a number of tasks involved in gaining nutrients from digested food:
- Ingestion
- Digestion
- Absorption
- Egestion
What is ingestion?
Ingestion is the taking in of food
What is digestion?
Digestion is the breaking down of ingested food into its component molecules
What is absorption in the digestive system?
Absorption is the extraction of nutrients from digested food
What is egestion?
Egestion is the system of disposing of waste from digested food
What are the different types of nutrients?
Nutrients can be placed into the following categories:
- Carbohydrates
- Proteins
- Fats and lipids
- Vitamins
- Minerals and trace elements
- Salts
What are carbohydrates?
Carbohydrates are a nutrient that provide an energy source for the human body
What are proteins?
Proteins are a nutrient that can be used to build cells and tissues in the human body
What are fats and lipids?
Fats and lipids are proteins with many uses in the human body: for example in hormone production
What are vitamins?
Vitamins are a nutrient that cannot be made by the human body and so must be extracted from food
What are minerals and trace elements?
Minerals and trace elements are nutrients that are used in the assembly of different structures in the human body
What are salts?
Salts are a nutrient that is fundamental to all cells in the human body
What are the components of the digestive system?
Components of the digestive system include:
- Oral cavity
- Tongue
- Oesophagus
- Liver
- Gallbladder
- Colon
- Appendix
- Anal canal and anus
- Stomach
- Pancreas
- Jejunum
- Rectum
What are the components of the mouth/ buccal cavity within the digestive system?
The components of the mouth/ buccal cavity that play a role in the digestive system are:
- Teeth
- Buccal lining
- Tongue
- Salivary glands
What is the role of teeth within the digestive system?
The role of the teeth within the digestive system is to masticate food. The muscles in the tongue, cheek and lips form a bolus from the food
What is the role of the buccal lining within the digestive system?
The buccal lining is a thick layer of un-keratinised stratified squamous epithelium. It has a high cell turnover rate to cope with the friction from chewing food
What is the role of the tongue within the digestive system?
The tongue is a mainly muscular structure. It is where the tastebuds are found
What is the role of the salivary glands within the digestive system?
There are three main sets of salivary glands: the parotid, sub-mandibular and sub-lingual. They all secrete saliva into the buccal cavity which serves a number of roles:
- Cleanses the mouth
- Dissolves food chemicals so they can be tasted
- Moistens food with mucin and water to help compact it into a bolus
- Contains enzymes that begin food digestion. Eg amylase and lipase
What is the role of the oropharynx and laryngopharynx within the digestive system?
These structures are made of epithelium tissue and rich in mucous glands, which smooths the passage for the food bolus which has entered from the mouth
The skeletal muscles in the walls of these structures run longitudinally and circumferentially to propel food into the oesophagus
What is the swallow reflex?
The swallow reflex is a complex and controlled event that allows food to access the oesophagus
What is a reflex peristalsis?
Once the swallow reflex allows food into the oesophagus, the reflex peristalsis takes over and propels food into the stomach
Describe the positioning of the oesophagus:
The oesophagus is a muscular tube about 25cm long. It runs through the diaphragm at the oesophageal hiatus and joins the stomach at the cardiac orifice where there is a smooth muscle sphincter which is closed, except for when food arrives
Describe the structure of the oesophagus:
The oesophagus is made up of the following:
- Serosa
- Muscularis
- Sub-mucosa
- Mucosa
What is the serosa?
The serosa is a connective tissue membrane that surrounds the oesophagus tube as its outermost layer
What are muscularis?
Muscularis are skeletal muscles running in different directions as the second most outer layer of the oesophagus
What is the sub-mucosa?
The sub-mucosa is a connective tissue layer beneath the muscularis
What is the mucosa?
The mucosa is a smooth muscle layer with connective tissue and lining epithelium that is the oesophagus’ innermost layer
Describe the stomach:
The stomach is a 15-25cm long muscular sac where further digestion takes place. When empty it has a volume of 50ml, and when full can hold 4Ls
What is the structure of the stomach?
The stomach’s wall is made up of epithelium tissue, within which are millions of deep gastric pits that produce up to 3Ls of gastric juice a day
What is the role of the stomach?
The gastric juice, pyloric region and pyloric sphincter act together to break the food (aka chyme) into small chunks ready for entry into the duodenum
Food starts to exit the stomach after approximately 30 minutes and has usually fully exited within 4 hours
What are the cells within the gastric pits?
The cells of the gastric pit are:
- Parietal cells
- Chief cells
- Enteroendocrine cells
What is the role of parietal cells within the gastric pits of the stomach?
Parietal cells secrete HCl to make the stomach’s environment acidic. It also releases a glycoproteins to absorb vitamin B12 in the small intestine
What is the role of chief cells within the gastric pits of the stomach?
Chief cells produce a protein digesting enzyme called pepsinogen that is converted by HCl into pepsin and a lipase
What is the role of enteroendocrine cells within the gastric pits of the stomach?
The enteoendocrine cells release a number of chemicals that act either locally or systematically (in the bloodstream)
What is the role of mucus glands within the stomach?
The stomach has mucus glands that produce a layer of alkaline mucus which traps a layer of bicarbonate rich fluid underneath. This protects the stomach’s epithelium from the acidic contents of the stomach
Describe the duodenum:
The duodenum is the first 20-25cm of the small intestine
What is the role of the duodenum?
The duodenum doesn’t secrete enzymes itself, but the secretions from the pancreas and gallbladder enter into the duodenum, which has major effects on the chyme
What are the excretions of the pancreas?
The pancreas secretes hormone endocrinely and pancreatic juice from the afinar cells exocrinely
What does pancreatic juice contain?
Pancreatic juice contains:
- Pancreatic amylase
- Lipase
- HCO3
- RNA and DNA
- Protease enzymes
What is the role of pancreatic amylase within pancreatic juice?
The role of pancreatic amylase is to digest carbohydrates
What is the role of lipase within pancreatic juice?
Lipase digests lipids
What is the role of HCO3 within pancreatic juice?
HCO3 neutralises HCl
What is the role of RNA and DNA within pancreatic juice?
RNA and DNA are used to digest DNA and RNA
What is the role of protease enzymes within pancreatic juice?
Protease enzymes continue the breakdown of proteins
What is the role of the gallbladder within the digestive system?
The gallbladder stores and concentrates bile produced by the liver, which helps to emulsify fats so they can be stored, and enables absorption of fat soluble vitamins and iron within the small intestine
Describe bile:
Bile is produced by the liver and stored in the gallbladder. It is a yellow/green liquid made mainly of H2O with bile salts. It contains no digestive enzymes
What is the role of bile within the digestive system?
Bile’s main role is to emulsify fats so they can be absorbed. It also enables the absorption of fat soluble vitamins and iron in the small intestine. The remainder of bile is bile pigments made from the breakdown of red blood cells
Describe the jejunum and ileum:
The jejunum and ileum form the remainder of the small intestine. The jejunum is 2m long and the ileum is 4m long
Describe the structure of the jejunum and ileum:
The inner surfaces of the jejunum and ileum are covered with villi to increase the surface area for absorption of nutrients
What is the role of the jejunum and the ileum within the digestive system?
The jejunum and ileum’s surface contains cells that absorb most nutrients to be released into the blood stream. This passes through the hepatic vein to the liver where processing of the food takes place. Nutrients from outside the body must cross the cells that make up the intestine wall to enter the inside. The villi on the jejunum and ileum’s surface helps speed up this process
Fats cross the cell wall and enter into a lacteal which leads into the lymph system which eventually drains into the venous system
What is the location of the large intestine?
The large intestine is 2 metres long. At its entrance is a sphincter (ring of muscle) which leads to the caecum which has the appendix at one end. Leading away from the caecum is the colon which leads to the rectum and finally the anal canal and anus
What is the structure of the large intestine?
The large intestine has longitudinal muscle modified to form three layers of smooth muscle which cause the tube to segment
What is the role of the large intestine?
The main role of the large intestine is to remove water and electrolytes from the gut’s contents
The large intestine has mucous cells which aid the movement of the faeces. Mobility in the large intestine is intermittent: mass movements take place by powerful tactile waves 3-4 times a day after eating to push the food into the rectum. Increased fibre shortens the transit time
Describe the rectum:
The rectum is 12-15cm long and usually empty until jut before defaecation
What is the role of the rectum?
Faeces enter the rectum from the colon due to mass movement which allows it to force its way in initiating the defecation reflex. This causes a relaxation of the internal smooth muscle sphincter of the anus. If this coincides with a voluntary relaxation of the skeletal muscle, then defection will take place
What are the liver and gallbladder in relation to the digestive system?
The liver and gallbladder are considered to be accessory organs of the digestive system
What is the role of the liver in the digestive system?
The liver’s roe is to process food arriving from the small intestine. It also filters blood to extract toxins and add important proteins
It can be considered a processing plant and a production facility
What is the structure of the liver?
The liver is compose of many small units called liver lobules. Each is a hexagonal structure comprising of plates of liver cells called hepatocytes
What is the structure of liver lobules?
Liver lobules are hexagonal structures of liver cells. They are called hepatocytes. At each of the six corners of the lobule is a portal triad with three structures:
- A branch of the hepatic artery (supplying oxygen-rich blood to the liver)
- A branch of the hepatic portal vein (carrying venous nutrient-rich blood)
- A bile duct
Explain the system of blood vessels in the liver:
At the corners of hepatocytes are three structures: hepatic artery, hepatic vein and bile ducts
Hepatic arteries supply oxygen-rich blood to the liver. Hepatic vein carries nutrient-rich blood
Blood from the hepatic vein and artery filter toward the central vein. As the blood passes, nutrients are extracted from the blood by cels, and materials are added
Secreted bile flows through tiny canals called bile canaliculi to the gallbladder for storage
Describe the gallbladder:
The gallbladder is a thin-walled green muscular sac about 10cm long
What is the role of the gallbladder?
The role of the gallbladder i to store and concentrate bile
What is the urinary system?
The urinary system comprises of two kidneys and two ureters that carry urine from the kidney to the bladder and urethra to be carried outside
What are the roles of the kidney within the urinary system?
The kidneys have six roles within the urinary system:
- Excretion
- Regulation of blood volume and pressure
- Regulation of solute concentration in the blood
- Regulation of extracellular fluid pH
- Control of rate of red cell production
- Regulation of vitamin D levels
Describe the kidney’s role of excretion:
The kidneys are the major excretory organ. They filter blood to remove metabolic wastes, toxins and excess ions
Describe the kidney’s role of regulating blood volume and pressure:
The kidneys play a major role in controlling extracellular fluid volume by varying the amount of fluid lost as urine. By controlling blood volume, this controls blood pressure in-turn
Describe the kidney’s role of regulating solute concentration in the blood:
The kidneys are essential in controlling the concentrations of ions in the blood, particularly: sodium, potassium, chlorine and calcium
Describe the kidney’s role of regulating extracellular fluid pH:
The kidneys secrete variable amounts of H+ to manage body pH. This is a significant contributor to the control of the whole body’s acid/base balance
Describe the kidney’s role in controlling the rate of red blood cell production:
The kidneys secrete a hormone called erythropoietin that stimulates bone marrow cells to produce more red blood cells
Describe the kidney’s role in regulating vitamin D levels:
The kidneys contribute to the control of blood calcium levels by activating Vitamin D
What is the renin-angiotensin-aldosterone mechanism?
This is a hormone system which regulates blood pressure and fluid:
When arterial blood pressure falls, renin is produced. Renin acts on angiotensin in the blood to produce angiotensin 1
Enzymes called angiotensin converting enzymes convert angiotensin 1 to angiotensin 2 which acts to raise the blood pressure
Angiotensin 2 also causes the release of the hormone aldosterone from the adrenal gland to cause a reduction in urine volume, therefore increasing blood volume and pressure
What is the role of anti diuretic hormone?
ADH is produced by the pituitary gland and released in response to decreased blood volume. It acts to increase reabsorption of water and sodium to reduce urine volume, therefore increasing blood volume
What are the structures of the urinary system?
The anatomy of the kidney is complex. It has structures designed for different functions:
1. The glomerulus- filters blood
- Descending loop of Henle and proximal convoluted tubule- reabsorber water and solutes
- Ascending loop of Henle- reabsorb solutes
- Distal convoluted tubule- reabsorber solutes and water under hormonal control
What is the cardiovascular system?
The cardiovascular can be broken down into a number of sub-topics:
- Blood
- Heart
- Blood vessels and circulation
Describe blood:
Blood is classed as connective tissue. It has cells, fibres (when clotted) and matrix
It has two main components:
- Plasma- fluid, dissolved proteins and metabolites
- Formed elements- blood cells and platelets
What are the roles of blood?
Blood is essential for respiration, nutrition, thermoregulation, immune defence, internal communication and water and pH balance
It has seven major functions:
- Carry oxygen from the lungs to the body
- Carry CO2 from the body to the lungs
- Deliver nutrients from the digestive system to the body
- Transport waste from the body to the kidneys and liver
- Defend from foreign organisms
- Defend against infection
- Transport hormones
What are the formed elements of blood?
The formed element of blood are:
- Red blood cells/ erythrocytes (45%)
- White blood cells/ leukocytes (1%)
- Platelets (54%)
What is the role of red blood cells?
The role of red blood cells is to transport oxygen from the lungs to the rest of the body
What is the role of white blood cells?
The role of white blood cells is to destroy invading organisms (eg bacteria) and assist in the removal of dead and damaged tissue cells
There are a number of subtypes of leukocytes: granulocytes and agranulocytes
What is the role of platelets?
The role of platelets is to provide the first line of defence against damage to blood vessels. Platelets are a major contributor to the clotting process
What is the structure of red blood cells?
Red blood cells are biconcave discs of 7-8um diameter. They have a flexible membrane to squeeze through small spaces
They have no nucleus, so are short lived. Old RBCs are broken down in the spleen by macrophages and recycled. The haem portion of haemoglobin is sent to the liver to be converted to bilirubin for removal in the bile
They contain haemoglobin to bind to O2 to carry it from the lungs to the rest of the body for respiration
The surface of RBCs is studded with glycoproteins and glycolipids to give the cell its blood type
What is the role of haemoglobin?
Haemoglobin is found in red blood cells. It contains Fe to bind to O2 to be carried from the lungs to the rest of the body
When carrying oxygen, haemoglobin becomes oxyhaemoglobin and is bright red. Without oxygen, it is deoxyhaemoglobin and dark red in colour
The amino acids of haemoglobin can bind to C02 to form carvaminohaemoglobin which enables RBCs to return some CO2 from respiration in the tissues back to the lungs to be exhaled
How are red blood cells produced?
Red blood cells are produced mainly in the bone marrow by a process called erythropoiesis, under the control of the hormone erythropoetin which is produced by the kidney
The number of RBCs is carefully monitored. They are typically produced at a rate of 2 million per second
What is the role of the plasma?
The plasma is the liquid component of blood. It’s role is to transport materials that are needed by or must be removed from cells
What is the structure of white blood cells?
White blood cells are larger than RBCs and have a nuclei. They do not contain haemoglobin
There are a number of anatomically and functionally different types of WBCs: agranulocytes and granulocytes
Where are white blood cells formed?
White blood cells are formed in the bone marrow and other lymphoid tissues
What are agranulocytes?
Agranulocytes are a type of white blood cell produced in the lymph nodes. They have few granules in their cytoplasm. They have a large nuclei
What are granulocytes?
Granulocytes are a type of white blood cell produced in bone marrow. They have granular cytoplasm and a lobed nucleus
How do blood types work?
All cells carry surface markers called antigens which are glycoproteins and glycolipids that convey their identity to other cells. There are two kinds of glycoproteins called A and B
The immune cells of a transplant host will look at the transfused cells to see if they are the same as their own. If they are different they will be recognised as foreign and the host’s immune defence mechanism will destroy the offending cells
What surface markers do each blood type have?
A- A
B- B
AB- both A and B
O- neither
What antibodies do each blood type have?
A- B
B- A
AB- neither (making it a universal recipient)
O- both A and B (making it a universal donor)
What is the rheus system?
The Rh factor is an genetically determined inherited characteristic, independent to the ABO blood types
If the Rh gene is present, the RBC will have he glycoproteins Rh+ on its surface. The allele is dominant bu if the gene isn’t present, the glycoprotein is absent and the person is Rh-
Opposing rheus genes can cause a foetus to be rejected by their mother
What is haemostats?
Haemostats is blood clotting. It is highly complex to ensure clots only occur when needed
Injury exposes collagen in the vessel wall and the damaged cells release chemical factors to:
- Cause smooth muscle in the vessel wall to contract- restrict flow
- Attract circulating platelets to the injury site to form a platelet plug
- Produce fibrin and cogulate to form a stronger clot/scab
After tissue repair, the clot is dissolved in fibrinolysis
What is the role of the heart?
The heart is two pumps working side by side: the right side pumps to the lungs, the left to the body
The role of the heart is to:
- Generate blood pressure
- Direct blood around the body
- Ensure one way flow of blood
- Regulate blood supply to meet metabolic needs
What are the resting and exercising heart rates of the human body?
Resting- 70bpm, 70ml stroke vol
Exercising- 190bpm, 5000ml vol
Describe the cardiac cycle:
Blood citing the heart is carried through the body by a complex network of arteries and vains. The rate of flow through this is dependent on the nature of the vessel and its diameter
Arteries have muscular walls that allow for expansion when the blood exits the heart, and recoils afterwards to maintain pressure in the artery all the way down to the capillary level
Veins don’t have muscular walls, so blood flow through them is more more uniform and at a lower pressure
Describe the pathway of nervous excitation of heart muscle:
- Vena cava
- Right atrium (valve)
- Right ventricle (valves)
- Pulmonary arteries
- Pulmonary veins
- Left atrium (valve)
- Left ventricle (valves)
- Aorta
- Coronary arteries
- Cardiac veins
Back into the right atrium
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