communication and Homeostasis Flashcards
what is and endocrine gland
it is a gland that secretes its product directly into the bloodstream rather than into a duct
what is homeostasis
the maintenance of a condition of equilibrium or of a near-constant internal conditions
what is a Receptor
a structure in the body that can detect changes in its environment and react to a stimuli
what is an Effector
a structure in the body that responds to a stimulus and brings about a response. In animals, muscles and glands are common effectors
what is the hormone Oestrogen
a female sex hormone that is a steroid and plays a role in the female reproductive cycle and the development of female secondary sex characteristics
however is also present in small quantities in males
define a synapse
a junction between two nerve cells, consisting of a minute gap across which impulses pass either by an electrical current or, more often, by diffusion of a chemical neurotransmitters.
where does paracrine signalling occur
between cells that are close together
where does endocrine signalling involve
signalling over longer distances, with the signalling molecule transported in the circulatory system
describe negative feedback
a type of control mechanism in which a change from the normal value of a physiological factor is detected and a response is made that restores its value back to its
norm
what is an endothermic animal
an animal that maintains its body temperature using heat generated within its body tissue
what is an exotherm animal
an animal that absorbs heat from its environment to help regulate its body temperature
define what specific heat capacity is
the energy needed to change the temperature of 1kg of a substance by 1 degree
how is heat lost from the body
Radiation
convection
conduction
evaporation
in terms of body heat loss what is radiation
is the loss of heat from hot objects into cooler surroundings. It is the main way in which the human body losses heat, but is also the way we gain heat from external sources, like the sun or fire
in terms of body heat loss what is convection
the movement of currents or warm air upwards, because the density of air decreases when it is warm
in terms of body heat loss what is conduction
it is the transfer of heat energy from a warmer material to a cooler one. The body can loose heat to the air by conduction, but, because the air is a good insulator, if a layer of air can be trapped around the body it will reduce further heat loss by radiation.
This is the reason why wearing thick closes are made of materials like wool that keeps you warm in cold conditions
what are the bodies cooling mechanisms
vasodilation of skin capillaries
sweating
flattening of the hair
what are the bodies warming mechanisms
boosting metabolic rate shivering vasoconstriction Erection of hairs behavioural homeostatic responses
what is a basal metabolic rate
the energy used by the body at rest to sustain its vital organs
what is the autonomic nerves system and what does it control
the part of the nervous system that controls automatic responses. It consists of the sympathetic and parasympathetic nervous system
what is the reason for the parasympathetic nervous system
known as the ‘rest and digest’ system as it conserves energy by slowing the heart rate, and increasing intestinal and gland activity
what is the reason for the sympathetic nervous system
activates the ‘fight or flight’ response
increases heart rate and other factors to allow the body to fight or flight
