Topic 3 Flashcards
How body temperature effects metabolic pathways.
Below tolerance limit - The rate of enzyme-catalysed ,metabolic reactions are too slow to maintain life processes in the cell. Above tolerance limit - The structures of the active sites of enzymes are altered which decreases the rates of enzyme-catalysed metabolic reactions.
How do endotherms control their body temperature
Decreasing environmental temperature - Increase the rate of respiration to generate more heat. Increasing environmental temperature - Decrease rate of respiration to generate less heat.
Water roles in body
Transport: Materials are transported around the body of a multicellular organism dissolved in water. Metabolism: All enzyme-catalysed reactions occur in solution inside the cells of an organism. Thermoregulation: Water has a very high specific heat capacity meaning a large quantity of heat must be transferred to change the temperature of a cell. This property allows organisms to maintain a constant body temperature. Movement: Water is essential for muscle movement in animals and mastic movements in plants such as the opening and closing of flowers. Sexual reproduction: Animals and plants that reproduce sexually use water to bring the male and female gametes in fertilisation. Support: Water-filled cells provide structural support for different tissue types in animals and plants.
What happens if the water range is out of the range of tolerance. (Osmoconformer and osmoregulator)
Cells shrink and become damaged when water availability is too low. Certain solutes such as sodium become more concentrated which affects the folding of polypeptides and reduces or inhibits enzyme activity. Above tolerance limit. Dome cells and tissues swell and burst when water availability is too high. The concentrations of certain solutes become too dilute and this reduces the rate of some life processes in cells.
What happens if blood glucose in outside range of tolerance.
Below tolerance limit - The rate of respiration is too low to maintain life processes. A person becomes hypoglycaemic and will have difficulty thinking as brain cells are not receiving enough glucose. If untreated, a person can lose conscientiousness and enter a coma. Above tolerance limit - A person becomes hyperglycaemic due to the high concentration of blood glucose. A condition called glycosuria develops in which glucose enters urine after exceeding the tolerance limit of 10 mmol/L. More water diffuses into urine by osmosis causing increased urination. A second condition called polyphagia develops in which a person eats excessively in response to the loss of glucose in urine. If untreated, hyperglycaemia can cause death and coma.
Outside tolerance limit for carbon dioxide.
Below tolerance limit: A condition called hypocapnia develops due to the decrease in concentration of carbo dioxide in the blood. Above the tolerance limit: A condition called respiratory alkalosis develops due to the decrease in concentration of hydrogen ions in the blood.
Outline the Stimulus response model
Simulus - Sensory receptor - Control centre - Effector - Respone. Sensory receptor - Sensory receptor responds to a stimulus. Sensory information is transmitted as nerve impulses from receptors to the control centre. Control centre - Receives and processes the information obtained from sensory receptors. The control centre then sends a signal to effectors. Signals are transmitted by nerve impulses (rapid) or hormones (slower). Effector - Responds to nerve impulses or hormones by opposing or enhancing the stimulus. Effectors in the body include sweat glands, arterioles in skin, skeletal muscles, and the erector (pili) muscles at the base of hairs.
Outline how Vasoconstriction and Vasodilation works.
Vasoconstriction - Body temperature is below the tolerance limit - Less heat is transferred from the blood to the skin and the external environemnt. Vasodilation - Body temperature is above the tolerance limit. More heat is transferred from the blood to the skin and the external environment.
Outline how contraction and relaxation of pili works.
Contraction - Body temperature is below the tolerance limit. Traps a thicker layer of air (thermal insulator) above the skin which reduces heat loss. Relaxation - Body temperature is above the tolerance limit. Less air is trapped above the skin which increases the rate of heat loss to the external environment.
The two types of nervous systems
Peripheral nervous system (PNS) - Nerves outside the brain and spinal cord. Function: Respond to sensory information and transmit the information to the brain and spinal cord. Central nervous system (CNS) - Brain and spinal cord. Function: Process sensory information and transmit nerve impulses to effectors in the body.
Neuron composition
Cell body - Contains the nucleus, cytoplasm, mitochondria, endoplasmic reticulum, ribosomes, the golgi body and lysosomes. Axon - A long fibre that conducts nerve impulses from the body to the dendrites to the cell body. Myelin sheath - An insulating layer that increases the rate at which a nerve impulse is conducted along the axon. Axon terminals - Small branches of the axon that form the connections (synapses) with other neuron in the nervous system. Extensions of the cell body that receive chemical signals from the axon termini of other neuron. Dendrites covet these signals into nerve impulses that are transmitted to the cell body.
Types of neurons
Sensory neuron - Conduct nerve impulse from sensory organs and sensory receptors to the central nervous system. Interneuron - Conduct impulses within the central nervous system. Interneurons real impulses over short distances from sensory neurones to more neurones. Motor neurons - Conduct impulses from the central nervous system to the effector glands, muscles or organs.
What is glycogenesis?
Glycogen is synthesised from glucose after meals
What is glycogenolysis?
Glycogen is broken down to release glucose between meals.
What does insulin does and glucagon do
Insulin seccreted by Beta-cells of pancreas when blood glucose is above the tolerance limit to decrease blood glucose concentration. Insulin stimulates the absorbtion of glucose from blood by cells in the muscle, liver, and fatty tissue. Stimulates glycogenesis inhibts gluconeogenesis and glycogenolysis.
Glucagon is secreted by alpha-cells in pancreas when blood glucose is below the tolernce limit it increases the blood glucose concentration. Stimulates release of glucose from blood by cells in the muscles, liver and fatty tissue. Stimulates glycogenolysis, stimulates glycogenolysis and gluconeognesis. Lastly, inhibts glycogenesis.
