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26 Blood and the circulatory system in humans Content and function of the blood Ethology a. Explain the work of Konrad Lorenz. b. Give a definition of: instinct, learning, imprinting, habituation, trial and error learning, classical conditioning and insight learning. Blood and the circulatory system in humans CIRCULATORY SYSTEM = an organ system that passes nutrients, gases, hormones, blood cells etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis = cardiovascular system + lymphatic system - cardiovascular system = blood + heart + blood vessels closed system - lymphatic system = lymph + lymph nodes + lymph vessels open system

Blood and Circulatory System in Humans

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Page 1: Blood and Circulatory System in Humans

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Blood and the circulatory system in humans Content and function of the blood

Ethology a. Explain the work of Konrad Lorenz.

b. Give a definition of: instinct, learning, imprinting, habituation, trial and error learning, classical conditioning and insight learning.

Blood and the circulatory system in humans

CIRCULATORY SYSTEM = an organ system that passes nutrients, gases, hormones, blood cells etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis = cardiovascular system + lymphatic system - cardiovascular system = blood + heart + blood vessels → closed system - lymphatic system = lymph + lymph nodes + lymph vessels → open system

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FUNCTIONS: 1. transportation of:

a. O2 from the lungs to tissues and organs b. CO2 from tissues to the lungs c. nutrients from digestive system to tissues d. waste products from tissues to kidneys e. hormones f. vitamins g. heat

2. regulation and maintenance of: a. constant pH of body fluids b. blood osmotic pressure c. temperature – water in plasma and its flow adjusts it

3. protection

a. blood clotting – prevents excessive blood loss b. immunity - antibodies, phagocytosis, interferons&complement – fighting against diseases

Heart (cor)

= a hollow cone-shaped muscular organ

- located in between the lungs, in the center of the chest cavity - the lower tip tilts toward the left - size of a clenched fist, length about 14 cm (from the top to the bottom) - weight about 280-320 g - layers:

• pericardium = a triple-layered sac that surrounds, protects and anchors the heart • pericardial fluid = located in the space between two layers, reduces friction and

moistens the surface • epicardium = the outer layer of the heart, provides protection • myocardium = the heart muscle • endocardium = the innermost layer of tissue that lines the heart, covers heart valves,

continuous with the inner lining of blood vessels - 4 chambers:

• divided by septum = partition into left and right part – each side divided into upper (atrium) and lower (ventricle) part

• atria – thin-walled, pump blood to ventricles • ventricles – thicker, contain more cardiac muscle, pump blood to the lungs and the

body • valves = tissues that prevent backflow of blood, keep blood flowing in the right

direction - the blood supply to the heart is provided by coronary arteries originating from the aorta

• left coronary artery – supplies the left part of the heart • right coronary artery – supplies the right part of the heart • small capillaries originate from coronary arteries, creating webs of capillaries

- blood flow: 1. superior and inferior vena cava bring deoxygenated blood to the right atrium 2. the right atrium contracts, the tricuspid valve opens, blood is pumped to the right

ventricle 3. the tricuspid valve closes, preventing backflow to the right atrium

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4. the right ventricle contracts, the pulmonary valve opens, blood is pumped into pulmonary artery and on to the lungs

5. the pulmonary valve closes, preventing backflow to the right ventricle 6. oxygenated blood returns from the lungs through pulmonary veins to the left atrium 7. the left atrium contracts, the mitral valve opens, blood is pumped into the left

ventricle (simultaneously with another contraction of the right atrium) 8. the mitral valve closes, preventing backflow to the left atrium 9. the left ventricle contracts, the aortic valve opens, blood is pumped into the aorta

and on to the body (simultaneously with another contraction of the right ventricle) 10. the aortic valve closes, preventing backflow to the left ventricle

- functional characteristics:

• excitability/irritability = the heart reacts to impulses from the heart itself and from the CNS, reacts by contracting

• contractility = it only reacts to impulses at the threshold or above → system of contraction is “all or nothing” – either maximum contraction or no contraction

• automaticity = the impulses for the contraction arise right in the heart, conductive muscle in the heart creates conduction system – this tissue generates electric action potential that causes the contraction - conduction system starts at the beginning of the right atrium with the sinoatrial

node which stimulates contraction of atria → through the muscles of the atrium passes to atrioventricular node → the stimulus is conducted through the bundle of His → the bundle branches to purkinje fibers and the endocardium and eventually ventricular myocardium

- SA node sends about 70 electric impulses per minute - the heart is innervated by autonomic nerves – sympathetic pathway increases

heart rate, parasympathetic pathway decreases heart rate • rhytmicity = heart rhythm has two phases: and diastole

- systole = the contraction of the heart muscle – blood is pumped from a chamber

- diastole = relaxation of the heart muscle – blood fills a chamber - atrial systole and ventricular diastole occur simultaneously – blood is pumped

from atria to ventricles

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- atrial diastole and ventricular systole occur simultaneously – blood is umped from ventricles to atria

- frequency of heart rhythm increases during physical and psychological stress - heart minute volume = volume of blood pumped through the heart in a minute,

about 5-5,6 liters • inexhaustibility = works for the whole life without getting tired

Blood vessels

= the part of the circulatory system that transports blood throughout the body - structure:

• perfectly smooth inner endothelial layer • muscle layer – circularly and spirally arranged smooth muscles • connective tissue surrounding the vessel on the surface, contains nerves that go into

the muscles - ARTERIES:

• their muscle layer is thicker than that of veins • all arteries are direct or indirect branches of the biggest artery aorta • aorta – originates in the left ventricle, turns left towards the spine, as thoracic aorta

passes through diaphragm, continues as abdominal aorta, branches into common iliac arteries

• thoracic aorta – supplies the chest and bronchi • abdominal aorta – its branches supply the kidneys, testicles or ovaries • common iliac arteries – supply pelvis and lower limbs • brachiocephalic artery – branches from aorta, branches into right common carotid

artery and right subclavian artery • common carotid artery – supplies the brain • subclavian artery – supplies neck, larynx, thyroid gland, shoulder muscles and chest

- VEINS: • their endothelial layer forms valves on certain spots • deoxygenated blood returns to the right atrium via the two biggest veins superior

vena cava and inferior vena cava • inferior vena cava – collects blood from the lower limbs, pelvis and chest • superior vena cava – collects blood from the head, neck and upper limbs

- CAPILLARIES: • create dense webs linking to the smallest arteries = arterioles • diameter 7-50 μm • total area in the body above 6000 m2 • no muscle layer, no connective tissue • function – exchange of gases in tissues

LYMPHATIC SYSTEM

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- blood does not pass nutrients directly to cells, because it flows in a closed circulatory system - in blood capillaries, blood plasma is filtered, nutrients leave blood → filtered plasma gets into extracellular matrix → here it forms interstitial fluid (IF) → it becomes lymph when it enters a lymph capillary

- lymph = less protein than IF, more fat droplets, waste materials and lymphocytes present - function – removes waste products from the cells, take part in the immune system - lymph returns to the blood in veins - lymph flow:

• through lymphatic vessels • can also have valves • lymph nodes – with accumulated lymphocytes, responsible for filtration and

destruction of bacteria and other harmful material

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Content and function of the blood

CHARACTERISTICS: - constitutes 8-9% of body weight - men – 5-6 liters - women – 4-5 liters - not equally distributed – most blood in veins, muscles and lungs - denser and more viscous than water - temperature 38°C - pH 7,35-7,45 – alkaline

FUNCTIONS: 4. transportation of:

a. O2 from the lungs to tissues and organs b. CO2 from tissues to the lungs c. nutrients from digestive system to tissues d. waste products from tissues to kidneys e. hormones f. vitamins g. heat

5. regulation and maintenance of: a. constant pH of body fluids b. blood osmotic pressure c. temperature – water in plasma and its flow adjusts it

6. protection

a. blood clotting – prevents excessive blood loss b. immunity - antibodies, phagocytosis, interferons&complement – fighting against diseases

CONTENT: - blood plasma + formed elements - hematocrit = ratio between the amount of plasma and elements

Blood plasma 55% = yellowish liquid

1. anorganic substances • water (90%) – bound to proteins or serves as a solvent • salts – NaCl, Na2CO3, etc. – important for maintaining of blood osmotic pressure

and pH • ions – Ca2+, etc. – important for bones, muscles and for blood clotting

2. organic substances • proteins (7%)

- albumins (54%) – produced by the liver – transport enzymes and sex hormones, keep blood osmotic pressure → keep water in plasma by binding it to itself

- globulins (38%) – produced by lymphatic tissue – important for immune system → immunoglobulins = antibodies destroy antigens

- fibrinogen (7%) – key protein in blood clotting

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- prothrombin – protein important for blood clotting • glucose

- level of glucose in blood = glycemia – regulated by hormones – insulin, glucagon, adrenalin, noradrenalin

- normal concentration – 4,5-5,5 mmol.l-1 - alimentary hyperglycemia = temporary increase in glycemia after food

ingestion • lipids • vitamins • hormones • bile pigments • urea, uric acid

Formed elements 45%

1. red blood cells = erythrocytes (99%)

• biconcave discs (diameter 7,4 μm, width 2,1 μm) → greater surface • lack nucleus and other organelles • cannot reproduce or carry on extensive metabolic activities • 3,8-4,8.1012 per liter • function – transport of O2 and CO2!

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• contain hemoglobin = O2 carrying protein, red blood pigment - consists of globin (protein part) and heme (non-protein part) - heme contains iron Fe, which binds O2 – weak bond → O2 can depart easily

in capillaries - adult male – hemoglobin 16 g/100 ml - adult female – hemoglobin 14,5-15,5 g/100 ml - 1 gram of hemoglobin binds 1,34 ml of oxygen → oxyhemoglobin

• erythropoiesis = production of RBCs - before birth – in liver and spleen of fetus - adulthood – only in red bone marrow - sufficient amount of protein, iron and vitamin B12 necessary - extrusion = ejection of nucleus occurs - regulated by hormone erythropoietin – its production depends on

atmospheric pressure • life span 100-120 days

- develop from myeloid stem cells → into reticulocytes → into RBCs - wear and tear as they squeeze through blood vessels - old RBCs removed by macrophages, hemoglobin split to globin and heme - adulthood – only in red bone marrow

2. white blood cells = leukocytes

• different shapes • have nuclei • 4.109 per liter • function – immune system!

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• types: A. granulocytes (70%) = contain granules visible under a light microscope

after staining, move actively, can change their shape, can go through the walls of capillaries

a) neutrophils – carry on phagocytosis (microphages), release enzymes lysosomes – destroy some bacteria

b) eosinophils – can also phagocytize, release enzymes that combat inflammation in allergic reactions

c) basophils – release heparin → prevents blood clotting, histamine, serotonin → intensify inflammatory and allergic reactions

B. agranulocytes (30%) = no granules visible after staining a) lymphocytes T – form in bone marrow, mature in thymus –

regulatory function – produce substances which support activities of other WBCs, live long

b) lymphocytes B – have receptors = immunoglobulins on their surface – when encounter antigens, lymphocyte B recognizes it and reproduces → develop into plasma cells which produce antibodies

c) monocytes – carry on massive phagocytosis (macrophages) • life span – a few days, during an infection a few hours (except for some B and T

lymphocytes – can live for years) - limited amount of phygocytized material before it interferes with the cells’

metabolism 3. blood platelets = thrombocytes

• they are not cells BUT small bodies [telieska] • disc-shaped • no nucleus, many vesicles • 100-300.109 per liter • produced from myeloid stem cells → develop into megakaryocytes → they

splinter into fragments (pieces of cytoplasm + cell membrane) in red bone marrow → enter bloodstream as platelets

• function – blood clotting! • life span – about 4-5 days

BLOOD CLOTTING = COAGULATION = a series of chemical reactions that culmination in the formation of fibrin threads, which stop the bleeding

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- process:

1. platelets get caught on the damaged wall of a blood vessel and at the strike, they fall apart and release clotting factors

2. clotting factors activate each other, causing prothrombin to change to thrombin 3. a transformation of soluble fibrinogen to insoluble fibrin, catalyzed by enzymes,

follows → fibrin fibers form a dense web, which captures platelets and other cells, forming a plug

4. the plug shrinks, expelling the blood serum (= plasma minus clotting proteins) → the thrombus = blood clot is smaller, but tighter and better encloses the wound in the wall of the blood vessel

- disorders:

• thrombosis = formation of blood clots even though no blood vessel was damaged

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- blood clot travels via blood through the body, can block a blood vessel and block the flow of blood into certain tissue → tissue dies

- if blood vessel supplying the heart muscle → myocardial infarction = heart attack - if blood vessel supplying the brain → brain stroke

BLOOD GROUPS AND BLOOD TYPES - cell membranes of RBCs contain protein antigens called agglutinogens → their presence or absence categorize blood into blood groups

• there are more blood types within a blood group

ABO blood group - agglutinogen A and agglutinogen B

• one person can have both, one of them or none - blood plasma contains antibodies called agglutinins, act against antigens

• agglutinogen A – agglutinin anti-A • agglutinogen B – agglutinin anti-B • if A and anti-A or B and anti-B meet → agglutination = aggregation of RBCs occurs →

can lead to death

- blood transfusion has to be done to avoid agglutination:

blood type can receive blood from

can donate blood to

nickname

A A, O A, AB -

B B, O B, AB -

AB A, B, AB, O AB universal recipient

O O A, B, AB, O universal donor

Rh blood group - named after Macacus rhesus monkey – first discovered in its blood - system of 13 antigens = Rh system

• most important is agglutinogen D: • if D present – Rh+ = Rh positive • if D absent – Rh- = Rh negative

- normally, blood plasma does not contain anti-Rh antibodies • BUT it appears if Rh- person comes to contact (e.g. via transfusion) with Rh+ blood →

causes hemolysis = rupturing of RBCs

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• disorder – hemolytic disease of the newborn – Rh incompatibility between mother and fetus (mother Rh-, fetus Rh+) → if fetus blood leaks into mother’s blood in placenta (not normally, but it can happen), she develops anti-Rh antibodies → antibodies pass into fetus’ blood through placenta and cause hemolysis

- Rh incompatibility between mother and fetus (mother Rh-, fetus Rh+) - if fetus’ blood leaks into mother’s blood in placenta (not normal, but it can

happen), she develops anti-Rh antibodies → antibodies pass into fetus’ blood through placenta and cause hemolysis

- antibodies production increases with each incompatible pregnancy, increasing the risk of damage to the fetus

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Ethology a) Explain the work of Konrad Lorenz.

b) Give a definition of: instinct, learning, imprinting, habituation, trial and error learning, classical conditioning and insight learning

- ETHOLOGY = the scientific study of animal behavior

• derived from Greek words – ethos = 'character,' logos = 'study' • subtopic of zoology • modern ethology started in 1930s with the work of Nikolaas Tinbergen, Konrad

Lorenz and Karl von Frisch → won Nobel Prize in 1973 • laboratory plus field science • interest in behavioral process rather than a particular animal group → study one type

of behavior in a number of unrelated animals

KONRAD LORENZ (Austria, 1903-1989)

- zoologist, founder of modern ethology - 1973 Nobel Prize for Physiology and Medicine - work, methods:

• described learning behavior in ducklings and goslings → at a certain critical stage soon after hatching, they learn to follow real or foster parents = imprint → demonstrated the phenomenon by imitating a mother duck, upon which the young followed him

• developed the idea of innate releasing mechanism to explain instinctive behaviors -

fixed action patterns - FIXED ACTION PATTERN = innate [vrodený] species-typical instinctive stereotyped

behavioral sequence that is indivisible [nedeliteľný] and runs to completion, produced by a neural network called innate releasing mechanism in response to sign stimulus/releaser = an external sensory stimulus

• once triggered by a sign stimulus, fixed action patterns proceeded in the absence of the triggering stimulus – e.g. egg retrieval by graylag geese proceeded even if the egg was removed after the behavior had been triggered by an egg lying outside the nest (http://www.youtube.com/watch?v=vUNZv-ByPkU)

- overall contributions: • understanding of how behavioral patterns may be traced to an evolutionary past • research on imprinting • study of instinctive behavioral acts and how they come about

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• proposed that animal species are genetically constructed to learn specific kind of information that is important for the survival of the species

• work on the roots of aggression and warlike behavior in humans – argued that it has an inborn basis but can be environmentally modified by the proper understanding of the basic instinctual needs of human beings

- INSTINCT = innate behavior = the inherent inclination of a living organism toward a

particular behavior • a behavior is instinctive if it is performed without being based upon prior experience

= in the absence of learning • examples: newly hatched sea turtles move toward the ocean, a kangaroo climbs into mother’s

pouch upon being born - LEARNING = the act or process of acquiring knowledge or of modifying existing knowledge,

behaviors and skills • the ability to learn possessed by humans, animals (and some machines) • may occur consciously or without conscious awareness • types: simple non-associative learning, associative learning, imprinting, observational

learning, play, enculturation etc. - IMPRINTING= any kind of phase-sensitive learning (= learning occurring at a particular age

or life stage) that is rapid and independent of the consequences of behavior • describes situation when an animal or person learns the characteristics of a stimulus

and the stimulus is said to be imprinted onto the subject • imprinting may have a critical period = a limited time when an event can occur →

incubator-hatched geese would imprint on the first suitable moving stimulus within 13-16 hours

• examples: newly hatched goslings imprint on their parents and follow them around, a baby learns

who its mother and father are

- HABITUATION = the psychological process in humans and other organisms in which there is a decrease in psychological and behavioral response to a stimulus after repeated exposure to that stimulus over a duration of time

• a form of non-associative learning • an animal first responds to a stimulus, but if it is neither rewarding nor harmful, the

animal reduces subsequent responses • example: if a stuffed owl is put into the cage of small birds, they react initially as though it we a real

predator → soon, they react less BUT if another owl put in, they react again (only a very specific stimulus is habituated to)

- TRIAL AND ERROR LEARNING = a method of reaching a correct solution or satisfactory result by trying out various means or theories until error is sufficiently reduced or eliminated

• example: An animal that is placed in an entrance must find the exit. As it proceeds, it finds a series of

branches. The animal must make a choice at each branch or fork. If it chooses the wrong one, it comes to a dead end. Then it must go back to take the other path. After a number of times the animal can run through the maze without making mistakes.

- CLASSICAL CONDITIONING = Pavlovian conditioning = Repeatedly pairing an unconditioned stimulus US (which unfailingly evokes a reflexive unconditioned response UR) with another previously neutral conditioned stimulus CS (which does not normally evoke the response). Following conditioning, the response occurs both to the unconditioned stimulus US and to the

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other, unrelated conditioned stimulus CS. The response to the conditioned stimulus is termed a conditioned response CR.

• a form of associative learning • demonstrated by Ivan Pavlov on his dogs in 1927 • example: Meat powder naturally will make a dog salivate when it is put into a dog's mouth;

salivating is a reflexive response to the meat powder. Meat powder is the unconditioned stimulus (US) and the salivation is the unconditioned response (UR). Then Pavlov rang a bell before presenting the meat powder. The first time Pavlov rang the bell, the neutral stimulus, the dogs did not salivate, but once he put the meat powder in their mouths they began to salivate. After numerous pairings of the bell, and then food the dogs learned that the bell was a signal that the food was about to come and began to salivate just when the bell was rang. Once this occurs the bell becomes the conditioned stimulus (CS) and the salivation to the bell is the conditioned response (CR).

- INSIGHT LEARNING = a type of learning or problem solving that happens all-of-a-sudden through understanding the relationships various parts of a problem rather than through trial and error

• example: After a chimpanzee was given two short sticks with a banana set out of reach, it

unsuccessfully attempted to reach the banana with the short sticks. The hungry chimpanzee gave up. However, the chimpanzee later accidentally discovered that the sticks could be joined together to form one longer stick. Just then, a spark of insight revealing a solution manifested, allowing the chimpanzee to successfully reach the banana.