B4 - Organising animals/plants Flashcards
What is the blood?
a liquid tissue consisting of mainly plasma (a transportation medium) in which red + white blood cells and platelets are suspended
What does the plasma carry?
-CO2 to lungs
-urea (from liver) to kidneys
-water
-small soluble products of digestion (glucose/amino acids) to individual cells
Always specify the products of digestion
It does not carry oxygen to cells
What are 4 functions of the blood?
-transporting O2 + nutrients to individual cells
-carrying away waste products to excretory organs
-carrying WBC + antitoxins/antibodies to destroy pathogens
-forming blood clots at wounds to prevent excess blood loss + prevent infections
Give 3 adaptations of the red blood cell:
-haemoglobin for oxygen to bind to, to be transported to cells for resp.
-biconcave disk (high SA:V)
-no nucleus to carry more oxygen
Explain why having more red blood cells per unit volume is an advantage to athletes:
-more haemoglobin
-more oxygen can be transported to muscle cells
-increases rate of respiration in muscle cells
-more energy released for muscular contraction to bring about movement
What is cardiac output and its formula?
-volume of blood pumped out of left ventricle per minute
-HRxSV
What is the heart?
an organ that pumps blood around the body in a double circulatory system
Name the parts of the heart in the order that the blood flows:
-vena cava
-right atrium
-right ventricle
-pulmonary artery (>lungs)
-pulmonary vein
-left atrium
-left ventricle
-aorta
Why might having only one ventricle make the circulatory system less efficient?
-oxygenated blood would mix with the deoxy. blood
-so less oxygen reaches body cells
What controls heart rate?
group of cells called the pacemaker in the wall of the right atrium
Describe the features of an artery and what it does:
-carries blood away from heart and usually oxygenated (apart from pulmonary)
-thick elastic walls to withstand high blood pressures
-strong muscular tissues to pump the blood
ARTERIES DONT HAVE VALVES
Describe the features of a vein and what it does:
-carries blood towards heart and usually deoxygenated (apart from pulmonary)
-thinner walls as it is lower pressure but has largest lumen
-valves that prevent backflow (blood squeezed back by skeletal muscles)
AND ARTERIES DONT HAVE VALVES
What is the purpose of the capillaries?
exchanges substances with cells (gives nutrients/oxygen for resp. and takes away waste products)
How are the capillaries adapted to their function?
-very small lumen but lots of them to increase SA
-always close to cells with one cell thick PPM for shortest diffusion distance
What is meant by a double circulatory system?
-goes through heart twice with 2 systems for every 1 circuit around the body
-one system takes blood from heart to lungs and back to be oxygenated and allowing CO2 to be excreted
-other system pumps fully oxygenated blood from heart to the rest of the body
Why is a double circulation system an advantageous feature?
-fully oxygenated blood and glucose can be pumped to the body very quickly (by the LV) to supply aero. resp.
-waste products are removed faster
-good for active animals
Describe coronary heart disease:
-fatty deposits build up in the vessel walls of the coronary arteries, making their lumens thinner
-this reduces blood flow to the heart muscle tissue
-less O2 and glucose are transported to the heart muscle cells so they perform less aero. resp. and more anaerobically
-produces lactic acid, which poisons the heart muscle cells resulting in a heart attack
Name 5 heart treatments:
-artificial pacemaker
-stents
-statins
-heart transplant
-heart valve transplant
(ASSHH)
Describe stents and their pros/cons:
-wire cage mesh that holds arteries open
-effective quickly and can be used anywhere, long-lasting
-risk of blood clots/infection
Inserted with a method called balloon angioplasty, where a catheter with a balloon on it holds the cage, inflating it so it holds the artery open
Describe what statins do and their pros/cons:
reduces production of “bad” cholesterol in liver (LDL)
-lowers risk of a fatty deposit build-up
-side effects + must be taken regularly
How does an artificial pacemaker help? Describe its pros/cons:
electrical device used to correct irregularities when natural pacemaker has irregular rhythm
-stabilises HR and is long lasting
-batteries need replacing sometimes
Describe what a heart transplant is and its pros/cons:
taking a donor heart and putting it into patient, can use artificial heart whilst waiting
-improved QoL + lifespan
-complex/expensive operation, immunosuppressants needed
What is a heart valve transplant?
replacing a faulty valve with a porcine/mechanical valve
Faulty can mean it doesn’t open/close properly
What are the features and consequences of a faulty valve?
-might not open/close fully (stiff/leaky)
-heart has to pump harder to deliver same amount of blood to body for respiration, causes shortness of breath and may result in heart failure
What is breathing? Explain what happens physically when you in/exhale:
-ventilating the lungs with air
-diaphragm contracts and flattens, intercostal muscles contract pushing ribcage up + out, chest volume increases, lower pressure draws air in
-diaphragm relaxes and curves up, IC muscles relax and ribcage goes down, chest volume increases, higher pressure pushes air out
Describe the process of gas exchange in the lungs:
-O2-rich air inhaled in alveoli, diffuses down steep CG across 1-cell thick PPM of the alveolus into the deoxygenated blood
-at the same time, CO2-rich blood meets with the less concentrated air so it diffuses down the CG and into the exhaled air
Name 3 adaptations of the alveoli:
-large net SA
-rich blood supply (capillaries) to maintain steep CG
-one cell thick PPM, shorter diff. path
Describe the anatomical path taken by air inhaled into the body:
-nose/mouth
-trachea
-bronchi (>lungs)
-bronchioles
-alveoli
Name and describe the 4 leaf tissue layers from top to bottom:
Excluding the vascular bundle
-upper epidermis (includes WC, waterproof/transparent)
-palisade mesophyll (lots of chloroplasts for PS)
-spongey mesophyll (air spaces + large SA for gas exchange with stomata and palisade cells)
-lower epidermis (stomata/GCs, control gas exchange/water loss)
Describe the function of the xylem and the substances it carries:
transports water + mineral ions from roots to stem/leaves by the transpiration stream
-water for PS and to hold itself upright
-ions for production of proteins/other molecules within cells
Describe the function of the phloem and the general function of substances it carries:
-transports dissolved sugars + cell sap made in leaves to the rest of the plant by translocation
-used for respiration/growth/storage
What is transpiration?
the loss of water vapour by evaporation from a leaf through the stomata
How does water get from the soil to the stomata?
transpiration stream
-osmosis into root hair cell then xylem
-up through plant to leaf
-spongey mesophyll, osmosis out and evaporates in air space
-diffuses out of stomata
In an exam, always say transpiration stream, rather than just transpiration
Summarise how the volume of water lost from the leaves is controlled:
Don’t describe how it happens
opening and closing of the stomata
Explain how the stomata and guard cells work together to regulate water loss:
more H2O - GC goes turgid and opens, to make an opening for water to be lost through
less H2O - GC goes flaccid and closes hole, so water is conserved
What environmental factors cause the stomata to open/close?
-open at day, closed at night (light in day, needs CO2 for PS)
-if CO2 conc. inside drops, they open to allow more in for PS
-wilting plants close stomata to lose less water
What factors affect the rate of transpiration and why?
-temperature (higher temp., water vapour evaporates quicker from cells)
-light intensity (more light, increases PS so stomata open more and let more water out whilst also letting CO2 in)
-humidity (more humid, less transp.)
-wind (more wind, CG more ventilated so water diffuses out quicker)
How do you measure the rate of transpiration?
-mass of plant lost due to transpiration
-volume of water absorbed by roots (using potometer, where bubble moves along scale)
What do the root, stem, and leaves make up in a plant?
the transportation organ system
How does oxygen get transported from the blood to the mitochondria?
diffusion down CG from blood across the cell membrane to mitochondria
Why is it an advantage for a leaf to have less stomata on the top of the leaf?
-less water lost from direct sunlight
-plant doesn’t wilt
What would happen if you left a plant with a potometer in a high temperature environment for a longer time?
-increased rate of transpiration
-leaves lose too much water from stomata and wilt (cells are plasmolysed)
-GCs also become plasmolysed, and so the stomata close to prevent excess water evaporation
-potometer bubble stops moving
It would stop moving if there was no more water to absorb
