Bio f4 chap 13 Flashcards
An employee had to work in hot conditions because the power supply in his office got cut off. Describe the response of the of the effectors in regulating his body temperature.
Mechanism of homeostasis:
- vasodilation occurs
- sweat glands secrete sweat
- erector muscles relax - body hairs are lowered
- skeletal muscles contract and relax lesser. body does not shiver
- the adrenal and thyroid glands are less stimulated - metabolism rate is lowered
A 40-year-old man was diagnosed by a doctor as unable to produce enough insulin. Describe what has happened to the man.
- excess glucose is not converted into glycogen
- the glucose level in the blood rises (hyperglycaemia) and glucose is excreted through the urine (glycosuria)
- the individual is considered as having diabetes mellitus
- A diabetic patient is constantly feeling thirsty, exhausted and lethargic and experiences weight loss
- if left untreated, it may lead to death
Ahmad has just finished a 100m sprint run. Explain how his blood pressure is lowered back to normal range.
- blood pressure rises
- the baroreceptor on the aortic arch and arterial carotid are stimulated
- the cardiovascular control centre in the medulla oblongata is stimulated
- the smooth muscles of the artery wall relax (vasodilation), hence reducing resistance to blood flow in the blood vessels
- the cardiac muscles contract weakly
- blood pressure returns to normal
Suggest two possible activities that can cause the walls of the collecting duct to become more permeable to water.
- eating salty foods
- drinking less water
An individual suffers damage in one kidney. Does the individual need to undergo haemodialysis? Suggest steps that this individual needs to take in order to go through his daily life without problems.
- does not need undergo haemodialysis
- needs to reduce food rich in protein and salt as well drink enough water
Explain the role of the liver when blood sugar levels decrease.
- slows down cellular respiration, converts glycogen to glucose and precents the conversion of glucose to glycogen
Explain the difference in the concentration of amino acids in blood plasma and urine.
- amino acid concentration in blood plasma is higher than that found in the urine
- reabsorption occurs
- 100% of the amino acids are reabsorbed into the blood capillaries through active transport at the proximal convoluted tubule
Both kidneys of a patient have failed. This condition causes water imbalance and an accumulation of urea in the blood. State the effect of kidney failure on the regulation of water balance in the blood.
- failed to function as osmoregulatory organ
- the water content in the body cannot be regulated
A patient suffered a disease that required the pancreas to be removed. Explain the effect of removing the pancreas on the production of the enzymes and hormones, and subsequently on digestion and blood glucose levels in the individual.
- absence of lipase (less fat digestion)
- absence of trypsin (less protein digestion)
- when insulin and glucagon are not produced, the regulation of blood sugar level is affected
What advice can be given to the patient to help him deal with the health problems caused by the removal of his pancreas?
- reduce the intake of carbohydrates
- get an insulin injection if the blood glucose level rises above normal
Mammals have different kidney structures depending on the presence of water in their habitats. The concentration of urine produced depends on the length of the loop of henle. The longer the loop of Henle, the higher the salt concentration in the fluid surrounding the loop of Henle. Based on this information, what can you predict about the loop of Henle in animals living in a humid environment compared to animals living in a dry environment?
- animals that live in a dry environment have a longer loop of Henle compared to animals living in a moist environment
- enables more water to be absorbed through the loop of Henle
- concentrated urine
Describe how thee body temperature of a worker who has been in a cold room for 6 hours is regulated.
- the body temperature of the worker drops after sitting in a cold room for 6 hours
- the thermoreceptors on the skin receive stimuli and transmit nerve impulses to the temperature control centre in the hypothalamus through afferent nerves
- vasoconstriction takes place (reduces the flow of blood to the skin surface and hence less heat flows to the surrounding)
- sweat glands are not stimulated (no sweating)
- erector muscles contract, causing body hairs to rise
- a thick layer of air is trapped on the skin surface and acts as a heat insulator that prevents the loss of heat through the skin
- body shivers
- the skeletal muscles contract and relax, generating heat and increasing body temperature
- the thyroid gland is stimulated to secrete thyroxine and the adrenal gland is stimulated to secrete adrenaline
- thyroxine increases cell metabolism rate and adrenaline increases glycogen conversion into glucose
- glucose is oxidised to yield heat energy
Breathing is an involuntary process that is controlled by the respiratory control centre in the medulla oblongata. Explain what happens to a climber’s breathing rate when he is at the peak of high mountain.
- less oxygen in the atmosphere
- oxygen partial pressure is low
- less oxygen in the blood
- detected by the peripheral chemoreceptors
- nerve impulses are generated and sent to the respiratory and cardiovascular control centres, then to the intercostal muscles, diaphragm and cardiac muscles
- rate of contraction and relaxation of the intercostal muscles and diaphragm increases
- increasing the breathing (inhale/exhale rate)
- heartbeat also increases
- more oxygen is brought to the cells and more carbon dioxide is transported to the lungs
Explain the importance of maintaining the body temperature at 37 degree celsius.
- the optimum temperature for all enzyme-catalysed chemical reactions is 37
- if the body temperature rises, enzyme-controlled metabolic reactions will be affected because the enzymes will become denatured
In your opinion, what is the effect on urine excretion if the food consumed contains large quantities of protein?
- protein is digested into amino acids
- excess amino acids are toxic and cannot be stored
- through deamination, the nitrogenous part of amino acids is converted to urea while the non-nitrogenous (carbon chain) part is converted to glycogen or fat for storage
- urea is a nitrogenous waste product that needs to be excreted through the urine
- since the urea concentration is high in a person who ate too much protein-rich foods, urea needs a lot of water to be excreted
- therefore, he will pass urine frequently
