Circulatory system, Respiratory system and excretory system Flashcards
Homeostasis
homeostasis is the state of steady internal, physical, and chemical conditions maintained by living systems.
The simple animals lacking specialized system for the transport and distribution are
Cnidarians, Flat worms and nematodes
In these animals materials exchange through direct diffusion through the body surface
Substances that are transported in the body include
respiratory gases (oxygen, carbon
dioxide), nutrients (glucose, amino acids, fatty acids, vitamins, etc.), waste products of
metabolism (urea, ammonia, etc), hormones and antibodies.
Interstitial fluid
Fluid found in the spaces around cells. It comes from substances that leak out of blood capillaries
open circulatory system
There is no distinction between the circulatory fluid and the interstitial fluid surrounding cells.
Heamolymph pumped from the heart bathes the body tissues directly. Back flow of heamolymph takes place via the pore (ostia.)
The open circulatory system has evolved in some invertebrate phyla such as
Arthropoda and Mollusca (some mollusc groups)
Back flow of the hemolymph takes place via
the pores (ostia)
The closed circulatory system has evolved in
vertebrates and invertebrates such as Annelids
Single circulation
During single circulation, in a complete circulation through the entire body, blood passes through the heart only once
In animals that demonstrate single circulation, posses two chambers in the heart. They are atrium and ventricle.
e.g.: Bony fishes, Cartilaginous fishes such as rays and sharks.
Double circulation
During double circulation, in a complete circulation through the entire body, blood passes through the heart twice.
e.g. Amphibians, Reptiles, Aves, Mammals
What is meant by incomplete double circulation
Amphibians contains a 3 chambered heart with 2 atria and 1 ventricle.
Some reptiles contains a 3 chambered heart with an partally separated ventricle.
In these animals O2 rich blood and O2 poor blood are mixed in the heart and hence it is known as incomplete double circulation.
3 layers of veins and arteries
Inner layer tunica intima containing simple squamous cells
Middle layer tunica media consisting of collagen fibres, elastic fibres and smooth muscles.
Outer layer tunica externa consisting mostly of collagen fibres.
Blood capillaries forms a network over all the tissues in the body except
Cornea and cartilage
Flow rate of blood and lymph
blood - 80 cm3s-1
lymph - 100 cm3h-1
Blood volume and mass in a human
5 dm3
5 kg
Exceptions of the general functions of veins and arteries
Arteries usually carry O2 rich blood however pulmonary arteries and umbilical artery transport O2 poor blood.
Usually veins carry O2 poor blood but pulmonary veins and umbilical veins transport O2 rich blood.
Largest artery and vein
Largest artery is the aorta while the largest vein is the inferior vena cava.
Differences between arteries and veins
Arteries have thick walls with muscle tissue. Veins have thinner walls and use valves to keep your blood flowing
The conducting system of the heart consists of
• SA node (Sinoatrial node)
• AV node (Atrioventricular node)
• Atrioventricular bundle (bundle of His), bundle branches and Purkinje fibres
Heart beat responds to a number of circulating factors including
Autonomic nervous system, hormones such as adrenaline and thyroxine and temperature.
SA node / Sinoatrial node
SA node is a small mass of specialized cells. It lies in the myocardium of the right atrium near the opening of the superior vena cava. The stimulus for contraction of the heart originates in the ‘SA node’. The SA node initiates the heart beat and sets the rhythm of the heart beat so it is called the pace maker.
SA node and AV node contains which type of cells
Neuromuscular
AV node
It is situated between wall of the left and right atria. The AV node transmits the electrical signals from the atria into the
ventricles.
Atrioventricular bundle (bundle of His), bundle branches and Purkinje fibres
The AV bundle branches and the Purkinje fibers transmit electrical impulse from the AV node to the apex of the myocardium. As a result of this impulse, wave of ventricular contractions begin. Then the contraction sweeps upwards and outwards pumping blood simultaneously into the pulmonary artery and the aorta.
Complete cardiac cycle lasts for
0.8 seconds
1. Atrial systole – 0.1 s
2. Ventricular systole - 0.3 s
3. Complete cardiac diastole – 0.4 s
At rest the healthy adult heart is likely to beat at a rate of
60- 80 beats per minute.
stroke volume
During a single contraction the amount of blood pumped by a ventricle is called the stroke volume which is about 70 ml
Why is there no wave for atrial repolarization in the ECG
As atrial repolarization and ventricular depolarization occurs at the same time weak atrial repolarization is masked by the powerful ventricular depolarization.
Systolic pressure
Systolic pressure is the pressure produced within the arterial system when the left ventricle contracts and pushes blood into the aorta. At rest , systolic pressure in a normal healthy adult systolic pressure is about 120 mmHg
Diastolic pressure
Diastolic blood pressure is the blood pressure within the arteries following ejection of blood at complete cardiac diastole(when the heart is at rest. In a normal healthy adult diastolic pressure is about 80 mmHg.
What causes pulses in arteries
The difference between systolic and the diastolic pressure causes pulses in arteries and hence this difference is referred to as the pulse pressure.
Arterial blood pressure is measured by
sphygmomanometer
Consequences of hypertension are
kidney damage, adrenal gland disorders, heart attack (because of the increased heart rate and cardiac contraction), stroke(caused by cerebral haemorrhage), damaged blood vessles which can lead to death
Causes of hypotension are
shock, Dengue hemorrhage fever, standing up suddenly from sitting or lying position, over bleeding/ hemorrhage condition, fasting, low nutrition etc
Consequences of hypotension are
Low blood pressure leads to inadequate blood supply to the brain. Depending on the cause unconsciousness may be brief (fainting) or prolonged (coma) possibly causing death.
Stroke
Similarly blockage due to atherosclerosis or rupture of arteries supplying blood to the brain (carotid arteries) may cause the death of nervous tissue due to lack of oxygen and nutrients. This is refered to as stroke.
2 commonly used surgical treatments for coronary obstructions
Angioplasty (placing of a stent)
Coronary artery bypass grafting
Lymphatic system is composed of
It consists of lymph vessels through which lymph
travels. Other structure in the lymphatic system includes lymph nodes, lymphoid tissues (tonsils) and lymphoid organs (e.g. spleen and thymus)
Lymph is circulated back to the circulatory system
At the base of the neck where lymph is pushed into the subclavian vein via 2 large ducts
Functions of human lymphatic system
e tissue drainage to maintain the blood volume in the blood circulatory system, absorption of fat and fat soluble vitamins from the small intestine and for immune responses.
lipoprotein
Lipoproteins are substances made of protein and fat that carry cholesterol through your bloodstream. There are two main types of cholesterol: High-density lipoprotein (HDL), or “good” cholesterol. Low-density lipoprotein (LDL), or “bad” cholesterol
Respiratory pigments
Respiratory pigments are organic compounds which can combine with oxygen where the partial pressure of oxygen is high and release oxygen where partial pressure of oxygen is low.
Haemoglobin
present in blood of human, other vertebrate and annelids. Fe is present (red)
Haemocyanin
present in hemolymph of arthropods and molluscs.
Cu (blue)
Chlorocruorin
present in the blood of many annelids. Fe (green)
Haemoerythrin
present in the blood of marine invertebrates. (some annelids). Fe is present (red)
Myoglobin
present in vertebrate muscles. Fe is present (red)
Myoglobin present in the muscle tissue has an oxygen storage function.
Bone marrow can be found in bones such as
Ribs, sternum, vertebrae and pelvis
Which hormone stimulates the production of red blood cells
Erythropoietin (from kidneys)
Red blood cells (erythrocytes)
Small biconcave disk like cells. Mature erythrocytes lacks nuclei. Lacks mitochondria and produces ATP by anaerobic respiration.
120 days of life span.
White blood cells (leukocytes)
Five types of leukocytes. They are Basophils, Lymphocytes, Eosinophils, Neutrophils and monocytes. Main functions of leukocytes are body defense, phagocytic engulfing and digesting microorganisms. Lymphocytes develop into T cells and B cells.
Platelets
Derived from bone marrow cells. Do not have a nuclei and plays major role in blood clotting.
Blood plasma
Contains inorganic ions in dissolved forms, plasma proteins such as albumin, antibodies and fibrinogen, nutrients, metabolic wastes, respiratory gases and hormones.
Protein concentration in plasma is higher than in interstitial fluid
pH of human blood
7.4
Serum
When clotting factors are removed from the plasma it is called serum.
Which substance prevents clotting
Heparin
Prevents conversion of prothrombin to thrombin and fibrinogen to fibrin
Used as an anticoagulant
A person’s first red blood cells are formed in the
Liver
Mass of an adult human heart
300g
Osmoregulation
Is the process through which organisms control solute concentration and water balance
Excretion
The removal of the nitrogenous metabolite and other metabolic waste products from the body is called excretion
Ammonia is produced during digestion of which organic compounds
Nuclei acids and proteins
Nitrogenous excretory products of animals are
ammonia, uric acid and urea
Ammonia in the process of excretion
It is the most toxic nitrogenous excretory product and it is the 1st nitrogenous excretory product formed in all organisms.
Animals excreting ammonia
bony fishes, many aquatic invertebrates and aquatic amphibians specially tadpoles
Urea in the process of excretion
In some animals ammonia is converted to urea in the liver by the active process of ornithine cycle
Animals excreting urea
Mammals, adult amphibians and sharks
Animals excreting uric acid
birds, reptiles, land snails and insects
Ascending order of energy cost of excretory products
Ammonia< urea< uric acid
Descending order of toxicity of excretory products
Ammonia>Urea>Uric acid
Descending order of water loss of excretory products
Ammonia>Urea>Uric acid
Green glands are used for excretion by
Two large glands found ventrally in the head anterior to the oesophagus.
Crustaceans
Sweat glands
Coiled tubular glands found in the dermis and is connected to the sweat duct which opens as a pore in the surface of the skin.
Found in mammals only
Salt glands
Paired glands found near the eyes which secretes excess salt
Marine birds and marine reptiles
Which excretory structures are not opend to the outside directly
Malphigian tubules
Function of kidneys
Produces urine to excrete waste products from the body while maintaining osmotic balance and acid-base balance.
Human urinary system consists of
two kidneys, two ureters, urinary bladder and
urethra
Location of kidneys
Found in the posterior abdominal wall each on either side of the vertebral column, behind the peritoneum and below the diaphragm
Peritoneum is a thin membrane which lines the inner surface of the abdominal cavity.
Right kidney is located slightly Lower than the left kideney
Gross structure of the kidney
Bean shaped organs held in position by a mass of fat and surrounded by a fibrous connective tissue.
3 areas, outer fibrous capsule, renal cortex and inner renal medulla.
Renal cortex is granulated due to the presence of glomeruli.
Apexes of the renal pyramids project into the renal pelvis through renal papillae.
two types of nephrons
cortical nephrons(reach short distance to the medulla)
juxta medullary nephrons (extend deep into the medulla)
Majority of the nephrones are cortical nephrones.
The efferent arteriole form two capillary networks
peritubular capillaries which surrounds the proximal and distal convoluted tubules
vasa recta which extend towards the medulla surrounding the loop of Henle
Podocytes
Inner layer of Bowman’s capsule consists of a single layer of flattened epithelial cells specialized for filtration known as podocytes.
Outer layer of the Bowman’s capsule composed of simple squamous epithelium
How is high blood pressure is maintained in the glomerulus
The efferent arteriole has smaller diameter than the afferent arteriole.
Capillary networks formed by the efferent arteriole and their location
Peritubular capillaries surrounding the proximal and distal convoluted tubules
Vasa recta surrounding the loop of henle.
What part of the nephron is impermeable to water
Ascending limb of the loop of henle.
Ultra filtration
Filtration of the blood under high pressure into the cavity of the Bowmans’ capsule is called ultra filtration
Filterate passes through the porus wall of blood capillary and the inner wall of the bowman’s capsule which contains podocytes specialized for filteration.
But due to their large size blood cells, plasma proteins and platelets do not pass through.
Glomerular filtrate contains salts, amino acis, glucose, vitamins and other small molecules.
Glomerular filtrate (components)
Contains all components of blood except red blood cells, white blood cells, platelets and plasma proteins
Selective reabsorption
Process through which useful molecules, ions and water from the glomerular filtrate are recovered and returned to the intestital fluid and then into capillary network of tubules is called selective reabsorption.
Most of the reabsorption occurs at the convoluted tubules.
Secretion
Secretion is the process by which foreign materials and substances not required to the body including waste are cleared from the peritubular capillaries and interstitial fluid into the filtrate
Major portion of water reabsorption occurs at which site
Proximal convoluted tubule
Normal blood osmotic pressure
300 mOsm/L
Hormone stimulating production of red blood cells
Erythropoietin
Role of kidney in homeostasis
Maintains electrolyte and water balance in body fluids
Excretion of toxic waste products from the body
Regulating blood pH through acid-base balance
Controlling blood volume and pressure
Secretion of erythropoetein hormone stimulating RBC production
Production and secretion of renin
Disorders related to human urinary system
Bladder and kidney stones
Kidney failure
Chronic kidney disease
Desired properties of a efficient respiratory surface
• It must be permeable, and wet so that gases can pass through by dissolving.
• It must be thin because diffusion is only efficient over short distances.
• It should possess a large surface area to allow a sufficient volume of gases to be exchanged according to the organism’s need.
• It should possess a good blood supply (maintain a steep diffusion gradient)
Respiration through body surface
Cnidarians, flatworms and earthworms
Respiration through external gills
Marine annelids
Respiration through internal gills
Fish, shrimp, prawns
Respiration through tracheal system
Insects
Respiration through lungs
Mammals, reptiles, birds
Respiration through skin
Amphibians
Respiration through book lungs
Spiders, scorpions
Vocal cords
Found in the larynx
Made up of elastic fibres
Helps produce sound
Nasal cavity, trachea and upper respiratory tract is lined by
Pseudo-stratified columnar
Mucus escalator
Beating of cilia helps to move mucus upwards towards the pharynx where it is swallowed into the esophagus.
Specialty of alveoli
Since there is no cilia in alveoli there are leukocytes to engulf foreign substances
Alveoli are also coated with a surfactant which prevents collapse under high tension
Main and accessory respiratory muscles
Diaphragm and inter-costal muscles
Muscles of neck, back, chest and abdomen
Breathing regulation
Main breathing regulation center is the medulla oblongata. Inspiratory center and the expiratory centers are included
In addition pneumotaxic center and the apneustic centers are found in the pons varoli.
Humans employ what type of breathing
Negative pressure breathing where air is pulled into the lungs.
Inhalation is active while exhalation is passive
Main respiratory muscles
Diaphragm and intercostal muscles
Events taking place during inspiration
Spontaneous stimulation of the inspiratory centre of the medulla oblongata sends impulses to the diaphragm and the inter-costal muscles. This causes the above mentioned muscles to constrict and increase the thoracic volume. Since the parietal pleura is adhered to the diaphragm and the inter-costal muscles along with the thoracic volume, lung volume also increases.This creates a low pressure area inside the lungs compared to the atmospheric pressure, so along the pressure gradient air is drawn into the lungs.
Events taking place during expiration
Spontaneous termination of the inspiratory centre of the medulla oblongata causes the respiratory muscles to relax.
Normal pH value of blood and major blood vessels
7.4
Aorta and carotid arteries
Effect of smoking
Nicotine addictive drug in cigarette smoke increases heart beat and blood pressure temporarily.
Cigarette smoke stimulates mucus secretion of goblet cells causing bronchitis.
HCN stops beating of cilia.
CO binds irreversibly with hemoglobin to produce carboxyheamoglobin
Pulmonary hypertension
High blood pressure in lungs
Tuberculosis
Caused by the bacteria Mycobacterium tuberculosis
Symptoms are loss of appetite and weight, excessive sweating, fever, racking of cough and spitting of blood.
Asthma
Characterized by wheezing and chest tightness
Respiratory cycle
Inhalation and exhalation during a single breath
Tidal volume
Volume of air inhaled or exhaled with each breath
500 ml
Inspiratory reserve volume
Extra volume of air that can be forcibly inhaled
Residual volume
Volume of air remaining in lungs even after a forceful expiration
1200 ml
Inspiratory capacity
Total volume of air that can be inspired after a tidal expiration
IC = TV + IRV
Functional residual capacity
Volume of air remaining in the lungs at the end of a tidal expiration
FRC = ERV + RV
Vital capacity
Maximum volume of air which can be inhaled and exhaled. Normally around 3100 ml in women and 4800 ml in men
VC = TV + IRV + ERV
Total lung capacity
Maximum volume of air that lungs can hold
6000 ml
TLC = VC + RV
Anatomical dead space
Some of the inspired air fills in to the system of trachea, bronchi and bronchioles and never contributes to the gas exchange
150 ml
Used to measure lung volumes and capacities
Spirometry test
What is meant by external and internal respiration
Transport of O2 from the lungs to the blood and movement of CO2 from the blood to lungs is referred to as external respiration.
Movement of O2 from blood to the tissue and CO2 from tissues to the blood is referred as internal respiration.
Flame cells are used for excretion by
Platyhelminthes(flat worms)
Nephridia are used for excretion by
Annelids, molluscs
Malphigian tubules are used for excretion by
Insectes and other terrestrial arthropods
Serum
When clotting factors are removed from the plasma it is called serum.
Chronic bronchitis
Tar in cigarette smoke stimulate goblet cells to secrete mucus and inhibits the ciliary action of cilia. As a result mucus and other contaminants accumulate in bronchioles narrowing them or completely blocking them.
Thus results in smoker’s cough which is an attempt to move mucus up the airway. In addition sufferers prouduce large amounts of phlegm which is a mixture of mucus, bacteria and WBCs.
Emphysema
Can occur as a complication of chronic bronchitis. Due to the constant inflammation of the lung tissue phagocytes line up in the lung tissue from blood capillaries. To reach the surface of the lungs phagocytes secrete elastace which digests the protein elastin. With much more less elastin alveoli does not stretch and recoil normally and as a result bronchioles and alveoli collapse.
Sufferers right part of the heart enlarges over time.
Other nitrogenous wastes products produced by humans
Creatinine and Uric acid
Creatinine is produced in the liver from certain amino acids where it is used in the muscles in the form of creatinine phosphate which acts as an energy store
Uric acid is produced during the digestion of purines of nucleotides.
An adult human produces how much urea
25-30g of urea per day
