Bio Flashcards
Explain the stimulus-response model of homeostasis.
The body detects a change (through Receptors) in the internal or external conditions (a Stimulus) and is responded to via feedback systems (Coordinator and Effector).
Stimulus -> Receptor -> Coordinator -> Effector -> Response
Differentiate between negative feedback and positive feedback. Examples?
Negative: Feedback minimises an excessive response. Example: Blood glucose, Temperature.
Positive: Feedback amplifies/continues a response. Example: Contractions in childbirth, blood clotting.
What is a Receptor, and what are the five receptors?
Receptors are specialised cells that detect change.
Examples: Photoreceptors (detect light), chemoreceptors (chemicals), nocireceptors (pain), mechanoreceptors (pressure, vibrations), thermoreceptors (temperature).
What are the 2 types of effectors, and how are their responses different?
Muscles and glands. Their response are different as muscles produce mechanical responses whilst, glands produce chemical, by releasing hormones into the blood.
Identify the different types of neurones.
Sensory, Connector and Motor.
Sensory - is sensitive to stimuli. (Receptors to CNS)
Connector - transmits messages between neurons. (CNS to CNS)
Motor - carry messages from CNS to Effectors. (CNS to Effectors)
Explain the process of the passage of a nerve impulse.
A nerve impulse is produced by dendrites.
It begins when a neuron receives a stimulus which travels down the axon as action potential, and channels open up as the threshold is met. It then reaches the axon terminal which releases the information into the next cell. (Think the structure of a neuron ->)
Define hormones and explain how they only activate specific target cells.
Hormones are chemical messengers, that mediate change. They do so by binding to their target cells, with the specific hormone receptors.
What is synaptic transmission?
The process of information (action potential) being communicated across a synapse, between two neurons.
What is metabolism?
Metabolism is the mechanism used to obtain energy alongside carbon for growth.
What is the difference between Autotrophy and Heterotrophy?
Autotrophy is when the organism obtains its carbon through inorganic substances such as the sunlight for plants.
Whilst, Heterotrophy is when the organism obtains carbon through an organic substance, like by eating another organism.
What are the types of metabolism?
Catabolism - The process of larger molecules break down into smaller molecules, to release energy stored in its chemical bonds.
Anabolism - The process of larger molecules building up from smaller.
What is signal transduction?
The process of converting the original stimulus signal into a response. This could increase or decrease in normal processes.
What are the steps of signal transduction?
Reception: The detection of the signalling molecule by a receptor.
Transduction: The relay of the signal into the cell.
Cellular Response: The activation of a cellular activity or process.
(Stimulus -> receptor -> etc)
Identify the thermoregulatory mechanism structural features.
Brown adipose Tissue: stores energy and burns energy to regulate temp.
Increased number of mitochondria per cell: means more efficient conversion of energy -> ATP, meaning more energy.
Insulation: reduces heat transfer by reflecting thermal radiation/or decreasing thermal conduction.
Identify thermoregulatory behavioural responses.
Kleptothermy: an animal shares in the metabolic thermogenesis of another animal.
Hibernation: Simplicity in thermoregulation to conserve energy.
Aestivation: the state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter.
Torpor: lowers body temperature (into energy conserving state) to survive harsh environmental conditions.
Identify thermoregulatory
physiological mechanisms.
Vasomotor control: vasoconstriction of blood vessels to reduce the exchange of heat with an environment.
Evaporation heat loss: evaporation removes heat and can act as a cooling mechanism.
Countercurrent heat exchange: an arrangement of blood vessels in which heat flows from warmer to cooler blood as a cooling mechanism.
Thermogenesis/metabolic activity from organs and tissues: a primary effector of thermoregulation in homeotherms and an important mediator of fever.
What is thermoregulation?
(Negative Feedback System)
The ability of an organism to keep its body temperature within certain boundaries even when the surrounding temperature is very different.
What is an endotherm and ectotherm?
Endotherm - maintains their internal body temperature, using heat generated within their body tissue.
Ectotherm - maintains their internal body temperature by absorbing heat from their environment.
Difference between structural, behavioural and physiological.
Structural: Physical structures.
Behavioural: A behaviour exhibited.
Physiological: Systems/functions.
Describe how antidiuretic hormone (ADH) and the kidney achieve osmoregulation.
Kidneys play a large role in human osmoregulation as they control the amount of water reabsorbed, which is controlled by hormones such as ADH (antidiuretic hormone).
ADH - helps the body conserve water when the fluid volume is low. Regulates the internal balance of water and dissolved materials. Water content of blood is low -> Brain produces more ADH -> more water is absorbed by kidney -> less urine -> water content is normal.
What is osmoregulation?
Osmoregulation is the maintenance of an internal balance between water and dissolved materials regardless of environmental conditions, by an organism.
What is an osmoconformer?
An animal whose body fluids are in osmotic balance with it’s environment. (Jellyfish)
What is an osmoregulator?
An animal that maintains a constant internal osmotic environment in spite of changes in it’s external.
What is hypertonic, hypotonic, and isotonic?
(Think of the solute/salt too)
Hypertonic: Means more water inside cell (hyper- more/ tonic-water).
Hypotonic: Means less water inside cell.
Isotonic: Balance.
What is ADH?
Is a hormone secreted by the pituitary gland that helps the body conserve water when the body’s fluid volume, specifically blood is low. Controls how much water is reabsorbed.
Types of Non-Infectious diseases.
Inherited - transmitted genetically during reproduction.
Nutritional - insufficient or inadequate diet.
Environmental - factors such as chemicals.
Types of Pathogens.
Virus, bacteria, fungi, protists, parasites, prions.
What is disease?
Any harmful deviation from the normal state of an organism. Can be infectious, or noninfectious. (Can be also called communicable)
What is the effect of the myelin sheath?
It insulates neurons and increased the speeds of impulses.
Identify and explain the various mechanisms that maintain water balance in plants.
Guard cells open and close the stomata, to regulate the amount of water.
Stomatal movement is the result of changes in the turgor of the guard cells.
High turgor
Identify the difference between infectious and non-infectious diseases.
Infectious: Disease caused by pathogens that can be transmitted.
Non-infectious: Disease caused by genetic or lifestyle factors, and are not transmissible between people.
