Module 5 Flashcards
What are the main divisions of the nervous system?
The Central Nervous system
The peripheral Nervous system
What does the CNS consist of?
The brain and spinal cord
What does the PNS consist of?
Nerves that connect the CNS to the rest of the body
What are the subdivisions of the PNS?
The somatic nervous system and the autonomic nervous system
What is the function of the somatic nervous system?
Controls conscious processes such as voluntary movements like running
What is the function of the Autonomic nervous system?t a
Regulates unconscious activities like breathing and heart rate
What are the branches of the Autonomic Nervous System?
The symapthetic and the parasympathetic nervous systems
What is the role of the sympathetic nervous system?
It initiates the fight or flight response by releasing noradrenaline
What is the role of the parasympathetic nervous system?
It triggers the rest and digest respons by releasing acetylcholine
What are the main parts of the brain?
- cerebrum
- hypothalamus
- cerebellum
- medulla oblongata
What is the cerebrum responsible for?
Higher brain functions like processing language, vision, thinking, emotions
What connects the 2 hemispheres together?
Corpus Callosum
What is the role of antagonistic pairs of muscles in movement?
Stretch receptors in the quadriceps muscle detect that the muscle is being stretched and send an electrical impulse along a sensory neuron to the spinal cord. In this case, the impulse is passed directly onto a motor neuron, which carries the impulse to the quadriceps muscle. The muscle contracts and causes the leg to straighten.
What are reflexes?
Rapid, unconscious actions that protect the body from harm
How does the blinking reflex work?
Sensory receptors in the cornea detect touch, triggering a reflex via the CNS to contract the eyelid muscles
How does the knee jerk reflex maintain balance?
Stretch receptors in the quadriucpec send signals to the spinal cord, causing the muscle to contract and the leg to straighten
What 2 systems activate the fight or flight response?
Endocrine system
Sympathetic nervous system
What hormone does the pituitary gland release during stress?
ACTH stimulates the adrenal gland to release cortiosl
What effect does adrenaline have on the body?
Increases heart rate
Increases breathing rate
Stimulates glycogenolysis
Caues hairs to stand on end
How does the medulla control heart rate?
By sending signals through the sympathetic and the parasympathetic nervous systems
What is the role of baroreceptors and chemorepectors?
Baroreceptors detect changes in blood pressure, Chemoreceptors detect changes in oxygen levels
pH in blood
How does the sympathetic system increase heart rate?
By releasing noradrenaline, which binds to receptors on the SAN to increase firing rate?
How does the parasympathetic system decrease the heart rate?
By releasing acetylcholine, which binds to the receptors on the SAN to reduce firing rate
What are the main components of a muscle fibre?
Sacrolemma (cell membrane)
Sacroplasm (cytoplasm)
T-tubules
Sacroplasmic reticulum
myofibrils
What are myofibrils?
Cylinders of protein within muscle fibres made up of sacromeres
What are the 2 main myofilaments in sacromeres?
Actin - thin filament
myosin - thick filament
What is a sacromere?
The functional unit if a myofibril defined by Z-lines at either end
How do muscles contract according to the silding filament theory?
Myosin binds to actin forming cross-bridges
ATP hydrolysis provides energy for myosin heads to pull actin filaments inward shortening the sarcomere
What happens when a muscle stops contracting?
Calcium ions are pumped back into the sacroplasmic reticulum, tropmyosin blocks actin-myosin binding sites and the sacromere lengthens
What are the main sources of ATP for muscles?
Areobic resporation in mitochondria requires O2
Anareobic respiration in cytoplasm produces lactic acid
Phosphocreatine anaerobic and alactic provides quick ATP
What is a neuromuscular junction?
A synapse between a motor neurone and a muscle cell, where acetylcholine is released to trigger muscle contraction
How does acetylcholine affect muscle cells?
it binds to the nicotinic cholinergenic receptors causing depolarisation and initiating muscle contraction
What are the 3 main types of muscles?
Skeletal, smooth and cardiac
What are the properties of skeletal muscle?
Striated, voluntary, fast- and slow-twitch fibres, multinucleate
What are the properties of smooth muscle?
Non-striated, involuntary, single nucleus, slow contractions
What are the properties of cardiac muscle?
Striated, involuntary, myogenic, does not fatigue
How can muscle fatigue be measured?
Using electromyography to record electrical activity in muscles as they contract and fatigue
How do alkaloids and tannins protect plants from herbivory?
Alkaloids taste bitter and are poisonous, while tannins also taste bitter and interfere with digestion, deterring herbivores.
What role do alarm pheromones play in plant responses?
Alarm pheromones warn other plants of herbivores, stimulating them to produce toxic chemicals or attract predators like wasps.
How does the Mimosa pudica plant protect itself from herbivory?
: It folds its leaves in response to touch, scaring or knocking off feeding insects.
How do plants respond to cold temperatures?
Plants synthesise antifreeze proteins to prevent ice crystals from forming inside cells.
Define phototropism and geotropism.
Phototropism is growth in response to light, and geotropism is growth in response to gravity.
How do plant shoots and roots differ in their phototropic responses?
Shoots show positive phototropism (grow towards light), while roots show negative phototropism (grow away from light).
How do plant shoots and roots respond to gravity?
Shoots show negative geotropism (grow away from gravity), while roots show positive geotropism (grow towards gravity).
Where are growth factors like auxins produced in plants?
Growth factors are produced in actively dividing regions such as shoots and leaves.
What is the effect of auxins in shoots versus roots?
Auxins promote cell elongation in shoots but inhibit growth in roots when in high concentrations.
Name two other plant hormones and their functions.
: Gibberellins stimulate seed germination and flowering; Abscisic acid (ABA) helps in stomatal closure and stress response.
What is the role of IAA in phototropism?
: IAA accumulates on the shaded side of shoots, causing cell elongation and bending towards the light.
How does IAA influence geotropism in roots?
IAA accumulates on the lower side of roots, inhibiting cell growth, causing roots to bend towards gravity.
What is apical dominance?
Apical dominance is the suppression of lateral bud growth by auxins produced at the apical bud.
What happens to side shoots when the apical bud is removed?
Side shoots grow because auxin levels drop, removing the inhibition.
How do gibberellins promote seed germination?
They stimulate the breakdown of starch into glucose, providing energy for growth.
How do auxins and gibberellins interact?
They can act synergistically (e.g., promoting stem elongation) or antagonistically (e.g., auxins inhibit side shoots while gibberellins promote them).
Which hormones regulate leaf abscission?
Auxins inhibit abscission, while ethene promotes it by breaking down cell walls in the abscission layer.
How does ABA cause stomatal closure?
ABA triggers the loss of potassium ions from guard cells, increasing water potential, causing water to leave, and the stomata to close.
How are auxins used commercially?
Auxins are used in rooting powders to stimulate root growth and in herbicides to kill weeds
How does ethene benefit the fruit industry?
Ethene is used to control ripening by breaking down cell walls and converting starch to sugars.
What is excretion?
Excretion is the removal of metabolic waste products from the body, such as carbon dioxide and nitrogenous waste (urea), to prevent tissue damage and maintain homeostasis.
What are the main functions of the liver?
Breaks down amino acids into urea (via deamination and the ornithine cycle).
Detoxifies the blood (alcohol, drugs, and hormones).
Stores glycogen.
Makes bile to aid lipid digestion.
What happens during deamination?
Deamination is the removal of the amino group from an amino acid, forming ammonia and organic acids. The ammonia is toxic and is converted into urea in the ornithine cycle.
What is the ornithine cycle?
The ornithine cycle converts ammonia (a toxic byproduct of amino acid breakdown) into urea, which is less toxic and can be excreted through the urine
What is the structure of the liver?
Hepatic artery: Delivers oxygenated blood.
Hepatic portal vein: Connects liver to intestines for detoxification.
Hepatic vein: Takes deoxygenated blood away.
Bile duct: Carries bile to the gallbladder.
What are hepatocytes?
Hepatocytes are liver cells that carry out most of the liver’s functions, such as detoxifying the blood and converting toxic substances into less harmful molecules.
What are nephrons?
Nephrons are the functional units of the kidney that filter blood, remove waste products, and regulate the body’s water and ion balance.
What is ultrafiltration in the kidneys?
Ultrafiltration occurs in the glomerulus, where blood is filtered under high pressure, pushing small molecules (e.g., glucose, urea, salts) into the Bowman’s capsule, while larger molecules like proteins remain in the blood.
What is selective reabsorption in the kidneys?
Selective reabsorption is the process by which useful substances like glucose, water, and ions are reabsorbed from the nephron back into the bloodstream.
How is water reabsorbed in the kidneys?
Water is reabsorbed mainly in the loop of Henle, distal convoluted tubule (DCT), and collecting duct by osmosis, with the amount regulated by hormones such as ADH.
What is the role of ADH in water regulation?
ADH (antidiuretic hormone) increases the permeability of the collecting duct, allowing more water to be reabsorbed back into the bloodstream, thus reducing urine volume and increasing blood water potential
What is the role of ADH in water regulation?
ADH (antidiuretic hormone) increases the permeability of the collecting duct, allowing more water to be reabsorbed back into the bloodstream, thus reducing urine volume and increasing blood water potential.
What is kidney failure?
Kidney failure occurs when the kidneys stop filtering waste from the blood. It can result from infection or high blood pressure and causes a buildup of waste products like urea, fluid imbalance, and ion imbalance.
How is kidney failure treated?
Kidney failure can be treated with dialysis (to filter the blood) or a kidney transplant. Dialysis requires regular hospital visits, while a transplant involves surgery and immunosuppressant drugs.
What is the function of the kidneys in regulating blood glucose?
The kidneys filter out excess glucose from the blood into urine when blood glucose is too high. They also reabsorb glucose back into the bloodstream when needed
How does pregnancy testing work?
Pregnancy tests detect the hormone hCG in urine. Monoclonal antibodies on a test strip bind to hCG, and a color change indicates a positive result.
How does drug testing in urine work?
Drug tests use antibodies on test strips to detect the presence of specific drugs. If the drug is present, the test strip changes color, and further testing (e.g., GC/MS) may be used for confirmation.
What is the process of glomerular filtration?
Blood is filtered in the glomerulus under high pressure. Small molecules are filtered into the Bowman’s capsule to form glomerular filtrate, while larger molecules stay in the blood.
How does the loop of Henle contribute to water reabsorption?
The loop of Henle creates a concentration gradient by pumping ions out of the ascending limb. This facilitates water reabsorption from the descending limb and distal parts of the nephron.
What is the role of Kupffer cells in the liver?
Kupffer cells are specialized macrophages that break down old red blood cells and remove bacteria from the bloodstream in the liver’s sinusoids.
What are the dangers of untreated kidney failure?
Untreated kidney failure can lead to a buildup of waste products (e.g., urea), ion imbalances, fluid retention, anemia, and potentially death.
What is homeostasis?
Homeostasis is the maintenance of a constant internal environment in the body, including conditions like temperature, blood pH, and blood glucose concentration.
What is a stimulus?
A stimulus is a change in the internal or external environment that causes a response from the organism.
How does the nervous system detect changes in the environment?
The nervous system detects changes through receptors that sense stimuli like light, pressure, and chemicals, which then send electrical impulses through sensory neurons to the central nervous system (CNS).
What are the roles of sensory, relay, and motor neurons in the nervous system?
Sensory neurons transmit impulses from receptors to the CNS, relay neurons pass impulses between sensory and motor neurons, and motor neurons send signals from the CNS to effectors (muscles or glands).
How do cells communicate through cell signaling?
Cells communicate via chemicals such as neurotransmitters and hormones, which are detected by receptors on the target cell’s membrane, allowing a response.
Why is homeostasis important for enzyme function?
: Homeostasis keeps temperature and pH stable, preventing enzyme denaturation. Changes in these conditions can cause enzyme structures to change, reducing their ability to catalyze reactions
What is the difference between negative and positive feedback mechanisms?
Negative feedback reverses changes to keep internal conditions stable (e.g., regulating body temperature), while positive feedback amplifies changes (e.g., blood clotting).
What happens during vasodilation and vasoconstriction?
Vasodilation: Arterioles widen, increasing blood flow to the skin, which helps cool the body.
Vasoconstriction: Arterioles constrict, reducing blood flow to the skin, helping to conserve heat.
: How does the body respond to a decrease in temperature?
Vasoconstriction reduces heat loss.
Reduced sweating.
Hairs stand up to trap air.
Shivering generates heat through muscle activity
How does the body respond to an increase in temperature?
Vasodilation increases blood flow to the skin to release heat.
Sweating cools the body by evaporation.
Hairs lie flat to reduce insulation.
How is blood glucose concentration regulated?
The pancreas releases insulin to lower high blood glucose and glucagon to raise low blood glucose, both through negative feedback loops.
What happens when blood glucose is high?
Insulin is released, increasing glucose uptake by cells and converting excess glucose into glycogen for storage in the liver and muscles.
What happens when blood glucose is low?
Glucagon is released, stimulating the breakdown of glycogen into glucose and the production of glucose from non-carbohydrates
How does the depolarization of beta cells in the pancreas result in insulin release?
High blood glucose increases ATP production, causing potassium channels to close, leading to depolarization, which opens calcium channels and triggers insulin release.
What is diabetes?
Diabetes is a condition where blood glucose levels are not properly regulated due to a problem with insulin production or response.
What causes Type 1 diabetes?
Type 1 diabetes occurs when the immune system destroys the beta cells in the pancreas, preventing insulin production
What causes Type 2 diabetes?
Type 2 diabetes is caused by the body’s cells becoming resistant to insulin, often due to poor diet, lack of exercise, or obesity.
How is insulin produced using genetically modified organisms (GMOs)?
The insulin gene is inserted into bacteria, which are grown to produce large amounts of insulin, which can then be harvested for medical use
What are stem cells and how could they be used to treat diabetes?
Stem cells are undifferentiated cells that can be converted into specific cell types, like beta cells. These could be used to regenerate insulin-producing cells in Type 1 diabetes.
