F214 - Communication Flashcards
Cell Signalling
Definition
The process by which cells communicate with each other
Cell Signalling
Examples
Neuronal and hormonal systems
Negative Feedback
Definition
A process that brings about a reversal of any change in conditions
It leads to homeostasis
Positive Feedback
Definition
A process that increases any change detected by receptors
Does not lead to homeostasis
Homeostasis
Definition
The maintenance of a constant internal environment
Negative Feedback Loop
Change in conditions detected by receptor
Impulse sent to the brain
Response impulse sent from the brain to an effector, either a muscle or a gland, to bring about a reversal in the change detected
The receptor detects any further change
Maintaining Body Temperature in Endotherms
Physiological Mechanisms
Sweat glands in the skin Lungs, mouth and nose Hairs on skin Arterioles leading to skin Liver cells Skeletal muscles
Maintaining Body Temperature in Endotherms
Behavioural Mechanisms - Too Cold
Putting on more clothes
Moving to a warmer place
Huddling to reduce surface area
Maintaining Body Temperature in Endotherms
Behavioural Mechanisms - Too Hot
Removing clothes
Moving to the shade
Opening windows
Water
Maintaining Body Temperature in Endotherms
Physiological Mechanisms - Sweat Glands
Too Hot
Temperature receptors in the skin detect an increase in temperature
Impulse sent to hypothalamus
Hypothalamus sends impulse to sweat glands
Sweat glands secrete more sweat
Heat energy is lost when sweat evaporates
Evaporative cooling
Maintaining Body Temperature in Endotherms
Physiological Mechanisms - Sweat Glands
Too Cold
Temperature receptors in the skin detect a decrease in temperature
Impulse sent to hypothalamus
Hypothalamus sends an impulse to sweat glands
Less sweat is secreted
Less evaporative cooling
Maintaining Body Temperature in Endotherms
Physiological Mechanisms - Skeletal Muscles
Too Cold
Temperature receptors in skin detect decrease in temperature
Impulse sent to hypothalamus
Hypothalamus sends impulse to skeletal muscles
Muscles contract rapidly
Respiratory rate of muscles increases
More heat energy released because of the inefficiencies in respiration
Maintaining Body Temperature in Endotherms
Physiological Mechanisms - Skeletal Muscles
Too Hot
Temperature receptors detect increase in temperature
Impulse sent to hypothalamus
Hypothalamus sends impulse to skeletal muscles
Shivering stops
Maintaining Body Temperature in Endotherms
Physiological Mechanisms - Liver Cells
Too Cold
Receptors detect a decrease in temperature
Impulse sent to hypothalamus
Hypothalamus sends an impulse to the liver cells
Metabolic rate of the liver increases
Rate of respiration increases
More heat released through inefficiencies in respiration
Maintaining Body Temperature in Endotherms
Physiological Mechanisms - Liver Cells
Too Hot
Receptors detect a increase in temperature
Impulse sent to hypothalamus
Hypothalamus sends an impulse to the liver cells
Metabolic rate of the liver decreases
Rate of respiration decreases
Less heat released through inefficiencies in respiration