Transport in Animals Flashcards
What does the Right Atrium do generally?
Receives DEOXYGENATED BLOOD from body tissues
What does the Right Ventricle do generally?
Pumps blood to the lungs in the Pulmonary Circuit
What does the Left Atrium do generally?
Receives OXYGENATED BLOOD from the lungs
What does the Left Ventricle of generally?
- Pumps blood to the body tissues in the SYSTEMATIC CIRCUIT
- Has thicker muscular walls than the right ventricle therefore greater pressure
What is the Septum?
The muscular wall that separates the ventricles from each other
What do the Tricuspid and bicuspid valves do?
Prevent the blood from flowing from the ventricles back into the atria
What do the Semilunar valves do?
Prevents high pressure blood from flowing from the arteries back into the ventricles
What is Cardiac muscle made of and what does it contain?
Branching fibres made from MYOFIBRIL TISSUE
Many Mitochondria to provide energy for contraction
What does each cardiac muscle cell contain?
Contractile units called SARCOMERES
Describe how and why muscle cells are separated
By interpolated discs to synchronise contractions
What do Coronary Arteries do?
Deliver nutrients and oxygen to the heart
What can happen if the Coronary Arteries are restricted?
Then the person can suffer a heart attack
Name the 3 stages of the Cardiac cycle
- Diastole
- Atrial Systole
- Ventricular Systole
What is the heart like during Diastole?
The Atria and Ventricles are relaxed
What is the heart like during Atrial Systole?
The Atria contract, Ventricles in systole
What is the heart like during Ventricular Systole?
The Ventricles contract, Atria in diastole
What happens in the Atrioventricular valves during the cardiac cycle?
- Blood in Atria pushes VALVES OPEN after ventricular systole
- BLOOD entering the heart flows through ATRIA INTO VENTRICLES (Diastole)
- Pressure in Atria and Ventricles rises
- Atria contract keeping the valves open
- After atria systole pressure in ventricles is higher than atria and the blood forces the valves closed
- Ventricles contract and tendinous cords prevent the valves from turning inside out
What happens in the Semilunar valves during the cardiac cycle?
- Before Ventricular systole, the pressure in the arteries is higher than in the ventricles, and the Semilunar valves are shut
- VENTRICULAR SYSTOLE quickly raises blood pressure and opens the valves
- Blood spurts out into the arteries at high pressure
- Once in DIASTOLE, Elastic Tissue in the heart helps the Ventricles Recoil and the Cardiac Muscles stretch out again
- The HIGHER PRESSURE in the Arteries causes the Semilunar Valves to CLOSE and again Tendinous Cords prevent the valves from turning inside out
What happens to Ventricular pressure throughout the cardiac cycle?
Diastole = LOW
Atrial Systole = Small bump/rise
Ventricular Systole = Huge increase in pressure
What happens to Atrial Pressure during the cardiac cycle?
Diastole = LOW
Atrial Systole = Small rise/bump
Ventricular Systole = tiny rise at beginning, rises very slowly
What happens in the Blood Vessels during the Cardiac Cycle?
- ARTERY WALLS are ELASTIC and SMOOTH the FLUCTUATIONS in pressure caused by the heart
- Elastic tissue also serves to MAINTAIN the PRESSURE as blood travels throughout the body
- The further along arteries the blood flows the lower the pressure becomes and the more dampened the fluctuations in pressure become
Describe the change in pressure as blood is pumped around the body, through what?
Aorta –>Arteries –>Arterioles –> Capillaries –> Venules –> Veins
As blood travels further along the cycle, pressure, and pressure fluctuations decrease.
Cardiac muscle is Myogenic, what does this mean?
It means it can contract on its own, without needing nerve impulses
Why is coordinated control of the atria and ventricles needed?
To synchronise the contractions to maximise the hearts efficiency
What is the SAN (Sino-Atrial Node) and what does it do?
The SAN is the patch of tissue that generates an electrical impulse that coordinates the contraction of Atria and Ventricles
State in detail the process of coordination of a heartbeat
- The SAN initiates a wave of excitation that passes through the walls of the Atria causing them to contract (Atrial Systole)
- The AVN at the top of the Septum and DELAYS WAVE from passing on to the Ventricles
- Short delay then the wave passes from the AVN down Purkine fibres in Septum to the bottom of the Ventricles
- Ventricular systole initiated at bottom of ventricles so as they contract, blood is pushed toward Semilunar valves that connect the Aorta and Pulmonary Artery to the heart
What is an ECG used for?
- Assess heart rhythm
- Diagnose cardiac Arrhythmia
- Diagnose heart attack
- Identify anatomical abnormalities on the heart
On an ECG, what does the P wave show?
Excitation of the Atria
On an ECG, what does the QRS complex indicate?
Excitation of the Atria
On an ECG, what does the T wave show?
It shows full heart diastole
Oxygen can bind reversibly, what does this allow it to do?
Allows it to be LOADED in the capillaries of the LUNGS and UNLOADED in the capillaries of the BODY TISSUES
What factor affects haemoglobin affinity for oxygen?
Partial pressure
How does the S-shaped curve of haemoglobin’s affinity for oxygen come about?
Binding of 1 Haem group triggers a conformational change exposing more subunits of oxygen, leading to the S-shaped curve
Haemoglobin has a low affinity for oxygen when in what?
Low partial pressures
Haemoglobin has a high affinity for oxygen when in what?
High partial pressures
Why does FOETAL haemoglobin have a slightly higher affinity for oxygen than adult haemoglobin?
To ensure the foetus can get oxygen from maternal blood through the placenta
CO2 travels in the blood in what 3 ways?
- 5% dissolves in the Plasma
- 10% combines with Haemoglobin to
- 85% is converted to hydrogen carbonate ions (HC03-)
How is C02 converted to hydrogen carbonate ions?
- C02 passes into RBCs and combines with water to form a weak CARBONIC ACID thats DISSOCIATES into hydrogen ions and hydrogen carbonate
- Charge inside the RBC is maintained by chloride ions moving in. (Chloride shift)
- Haemoglobin can act as a buffer by binding H+ ions to form haemoglobin acid
= Haemoglobin unloads oxygen in the body tissues and binds H+ ions in the process of CO2 transport away from body tissues
What is the Bohr effect?
That haemoglobin’s affinity for oxygen is inversely related to both acidity and to the concentration of carbon dioxide
How does the Bohr effect work?
- H+ ions from CO2 transport make RBC cytoplasm more acidic
- Conformational change in haemoglobin triggered by acidity reduces affinity for oxygen
- Oxygen unloaded in locations where lots of respiration (and CO2) production occurs and oxygen is required
- Ensures haemoglobin will load oxygen more easily in the pulmonary capillaries
(Low CO2 = High 02 affinity)
and unload easily in the tissue capillaries
(High C02 = Low 02 affinity)
What is hydrostatic pressure?
The pressure exerted by a fluid pushing against the sides of a container – forces water away
What is Oncotic pressure
The pressure created by osmotic affects of solutes == pulls water in
Explain how tissue fluid is formed?
- At the arterial end of a capillary bed high hydrostatic pressure forces water and solutes in blood plasma through the thin capillary wall
- Tissue fluid containing nutrients and oxygen surrounds body cells
- At the venous end, high oncotic pressure in the tissue fluid and low hydrostatic pressure in the capillaries means water and some solutes drain back into the capillaries.
- The rest of the tissue fluid drains into the lymphatic system
What 3 things will an effective circulatory system have?
- A FLUID MEDIUM for carrying nutrients, oxygen and wastes
- PUMP, to create pressure and flow
- Exchange surfaces
What type of circulatory system do mammals use vs fish?
mammals = Double circuit fish = Single circuit
What is the pulmonary circuit vs the systemic circuit?
In double circulatory systems,
- Pulmonary circuit goes to the lungs
- Systemic circuit goes to the heart and rest of the body
What is a disadvantage of single circuit circulatory systems?
Pressure drops as blood passes through small capillaries of the gills/exchange surface
- Rate of flow and thus delivery/removal is limited
The two circuits of a double circulatory system have differing blood pressure, how does it differ?
- Bp is lower in the Pulmonary circuit
- Bp higher for systemic circuit
What is the function of an Artery?
- Maintain HIGH PRESSURE of the blood
- Must be able to FLEX and RECOIL to withstand pumping of the heart and maintain pressure
What is the function of an Arteriole?
Deliver blood from Arteries to the Capillaries
What is the function of a Capillary?
- Deliver nutrients to the body tissues
- Removing the waste products of metabolism
What is the function of a Venule?
Deliver blood from the Capillaries in body tissues to the Veins
What is the function of a Vein?
- Transport blood back to the heart at low pressure
- Don’t need to stretch and recoil so can have thinner walls
- Valves prevent low pressure blood flowing in the wrong direction
Describe the structure of an Arteriole
NARROW with a layer of SMOOTH MUSCLE in the wall
Describe the structure of a Venule
NARROW vessels with thin layers of muscle, elastic tissues and collagen
What type of blood vessels have narrow lumen?
Arteries, to maintain high pressure of the blood
What type of blood vessels have wide lumen?
Veins, as they’re transporting
low pressure blood back to the heart
Describe the structure of a capillary (3)
- Walls, lumen, permeability
Narrow walls - one squamous endothelial cell thick
Narrow lumen
Permeable, leaky walls