Topic 7 Flashcards

Question

Explain electrocardiograph

Answer 1

-P wave is atrial contraction (wave of depolarisation) -QRS complex is ventricular contraction (wave of depolarisation) -T is ventricular relaxaton (wave of repolarisation) -Can be used to diagnose heart issues e.g heartbeat is fast or slow

Answer 2

-Medulla oblongata controls breathing rate and has 2 ventilation centres inspiratory and expiratory -Inspiratory centre sends nerve impulses to diaphragm muscles causing contraction -This increases volume and lowers pressure in the lungs -Inspiratory can also send singals to expiratory to inhibit its actions -Air enters lungs due to pressur e difference between outside and inside -The lung's stretch receptors are stimulated and send impulses to medulla oblongata which inhibit inspiratory centre -Expiratory centre becomes uninhibited which sends nerves to diaphragm to relax causing lungs to deflate and the body to exhale -The stretch receptors inactivate, inspiratory centre unihbits and the cycle repeats

Answer 3

-Excerise increases breathing rate by decreasing blood pH -During excersise, CO2 levels increase and decreases blood pH -Chemoreceptors in the medulla oblongata, aortic and carotid bodies detect a decrease in blood pH -A nerve impulse is sent to medulla oblongata which sends more frequent nerves to the diagragm -This increases rate and depth of breathing also triggering an increase in speed of gas exchange

Answer 4

-Medulla oblongata controls heart rate via the cardiovascular control centre -The CCC controls the rate at which the SAN fires - the SAN generates electrical impulses causing contraction -Animals need to alter heart rate to respond to internal stimuli e.g not faint -Chemical receptors detect stimuli e.g baroreceptors detecting pressure changes in aortic and carotid bodies and chemoreceptors to monitor O2 and CO2 levels in the blood -Eletrical impulses are sent to the medulla oblongata along sensory neurones -CCC processes the information and sends it to SAN through para/sympathetic neurones -Sympathetic is the fight or flight response - increases heart rate -Parasympathetic is the rest and digest response - reduces heart rate

Answer 5

-Maintenance of a stable internal enviroment, involves control systems to keep your body in narrow limits -Keeping the internal enviroment constant is vital for cells to function normally (>40 = denature enzymes) -Cells need a constant energy supply so blood glucose concentration must be stable - this is monitored by the pancreas -Water is essential to keep the body functioning, blood water levels must be constant - regulated by kidneys

Answer 6

-Used to reverse a change -Homeostatic systems involve receptors, comms system and effectors -Receptors detect when a level is high or low and this information is relayed via nervous system or hormonal system to effectors -Effectors respond to counteract the change bringing the level to normal and is named the negative feedback mechanism -Negative feedback keeps things around the normal limit e.g body temp to 37 -If a change is too big, effectors may not be able to counteract e.g huge body temp change

Answer 7

-Used to amplify a change from normal levels -Some changes may react positively -The effectors respond to further change the levels -Positive feedback aims to rapidly activate something e.g blood clot -Isnt involved in homeostasis as it does not stable the levels

Answer 8

-Sweating, more sweat secreted from sweat glands when hot which evaporates from the body -Hairs provide insulation by trapping air, when hot the pili muscles relax to not trap air and provide less insulation for heat loss -Vasodilation, more blood flows through capillaries so more heat is lost from the skin by radiation -Shivering, muscles contract in spasms. More heat is produced from inreases respiration -Less sweating, less sweat loss reducing amount of heat loss -Vasoconstriction, arterioles constrict reducing blood flow and heat loss via radiation -Hormones, body produces more adrenaline and thyroxine to increase metabolism leading to producing more heat

Answer 9

-Controls body temperature -Hypothalamus recieves information about temperature from thermoreceptors -Thermoreceptors send impulses along sensory neurones to hypothalamus which sends impulses along motor neurones to effectors (muscles & glands) -Effectors respond to restore body temperature back to the normal level

Answer 10

-Proteins called T.F control transcription of genes by binding to DNA sites near start of genes and increasing or decreasing rate of transcription (increase = activate, decrease = repress) -Some hormones work inside cells e.g normal temp means thyroid hormone receptor binds to DNA at start of gene, decreasing transcription for a protein to increase metabolic rate -So at colder temperatures thyroxine is released to bind to the thyroid hormone receptor

Answer 11

-Keyhole surgery is a way of doing surgery without making a large incision -Surgeons make a smaller incision and insert a video camera and specialised medical instruments through the incision -Operations dont involve opening patient, less blood loss and less scarring -Patient feel less pain and recover faster, athelete can return to competing quicker -Prostheses can replace damaged body parts e.g used to replace whole limbs or parts of limbs -Prostheses can include electronic devices that pick up signals sent by the nervous system -Those with damages knee joints can have protheses ones -Metal device is inserted into kneww to replace damage cartilage and bone-