Chapter 4 Flashcards
Biotic factors
Presence or absence of living things.
Optimum range
Range in which organism thrives best.
Outside the optimal range
Survive not thrive
Outside optimum rage
Suffer physiological stress and hypothermia
Niche
Environmental conditions, particularly abiotic factors well suited.
Extra cellular
Tissue or fluid Outside the cell
Intracellular
Liquid inside the cell
Eg Cytosol
Homeostasis
The maintenance of a relatively constant internal state despite changes in the external environment within small tolerances.
Stimulus response pathway
Stimulus receptor process centre effector response
Stimulus
A condition or signal the causes a response
Receptor
Cell of gland that detects a stimulus.
Effector
Cell, muscle of gland that carries out the response.
Chemoreptor
Chemical stimulus
Mouth nose
Mechanorexepter
Mechanical stimuli
Pressure, stretch
Skin ear
Photoreceptors
Light
Thermorecepter
Hot and cold
Nocicepter
Pain
Osmorecepter
Water
Brain hyper thalamus
Positive feedback
Enhances the original stimulus
Negative feedback
Cancels of contracts the original stimulus.
Conduction
Heat transferred through direct contact, hot to cold.
Convection
Transfers heat when hot air or water rises and replaced by cooler air.
Evaporation
When water is evaporated and cools the skin
Radiation
When infrared waves transfers heat from the object.
Vasodilation
Arterioles become wider. Move away from the core. Heat moves to the skin to be lost
Vasoconstriction
Artiroles constrict and move inward to the core to conserve heat
Hypothalamus
Controls baddy temp and water…..
Endotherms
Are capable of producing their own heat
Ectotherms
Rely on external sources for heat.
Homeothermic
Maintains stable internal temperature regardless of external environment.
Poikilothermic
Relies on external heat. Temperature varies
Structural adaptation
Shape size
Physiological adaptation
Chemical
Organs
Behavioural adaptations
Burrowing
Conscious movement
Beta cells
Insulin
Glucagon
Alpha cells
Hyperglycaemia
High concentration of glucose in blood
ADH
Hypothalamus
Makes the kidney more permeable
Metabolism
All chemical process in the body
Thyroxine
Increases metabolic activities within most tissues
TSH
Thyroid
Stimulating hormone between pituitary gland and thyroid gland
TRH
Thyrotrophin
Releasing hormone that is between hyper thalamus and pituitary gland
Single hormone
Hyperthyroidism
Too much thyroxin/ overactive thyroid gland
Hypothyroidism
Too little thyroxin/ not active enough
Gland swells- goitre
Abiotic factors
Physical and chemical factors
Eg temp, water, gases.
