communication and Homeostasis

Question 1

what is and endocrine gland

Answer 1

it is a gland that secretes its product directly into the bloodstream rather than into a duct

Question 2

what is homeostasis

Answer 2

the maintenance of a condition of equilibrium or of a near-constant internal conditions

Question 3

what is a Receptor

Answer 3

a structure in the body that can detect changes in its environment and react to a stimuli

Question 4

what is an Effector

Answer 4

a structure in the body that responds to a stimulus and brings about a response. In animals, muscles and glands are common effectors

Question 5

what is the hormone Oestrogen

Answer 5

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

Question 6

define a synapse

Answer 6

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.

Question 7

where does paracrine signalling occur

Answer 7

between cells that are close together

Question 8

where does endocrine signalling involve

Answer 8

signalling over longer distances, with the signalling molecule transported in the circulatory system

Question 9

describe negative feedback

Answer 9

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

Question 10

what is an endothermic animal

Answer 10

an animal that maintains its body temperature using heat generated within its body tissue

Question 11

what is an exotherm animal

Answer 11

an animal that absorbs heat from its environment to help regulate its body temperature

Question 12

define what specific heat capacity is

Answer 12

the energy needed to change the temperature of 1kg of a substance by 1 degree

Question 13

how is heat lost from the body

Answer 13

Radiation
convection
conduction
evaporation

Question 14

in terms of body heat loss what is radiation

Answer 14

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

Question 15

in terms of body heat loss what is convection

Answer 15

the movement of currents or warm air upwards, because the density of air decreases when it is warm

Question 16

in terms of body heat loss what is conduction

Answer 16

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

Question 17

what are the bodies cooling mechanisms

Answer 17

vasodilation of skin capillaries
sweating
flattening of the hair

Question 18

what are the bodies warming mechanisms

Answer 18

boosting metabolic rate 
shivering 
vasoconstriction
Erection of hairs 
behavioural homeostatic responses

Question 19

what is a basal metabolic rate

Answer 19

the energy used by the body at rest to sustain its vital organs

Question 20

what is the autonomic nerves system and what does it control

Answer 20

the part of the nervous system that controls automatic responses. It consists of the sympathetic and parasympathetic nervous system

Question 21

what is the reason for the parasympathetic nervous system

Answer 21

known as the ‘rest and digest’ system as it conserves energy by slowing the heart rate, and increasing intestinal and gland activity

Question 22

what is the reason for the sympathetic nervous system

Answer 22

activates the ‘fight or flight’ response

increases heart rate and other factors to allow the body to fight or flight