5.1.1 Communication and homeostasis

Endotherms

________ also use behavioral responses to temperature changes.

respiratory rate

The ________ can be controlled in the liver, releasing more heat when the body is too cold, and less when too hot.

thermoregulatory centre

The ________ in the hypothalamus monitors blood temperature, detecting changes in the core body temperature.

heat loss gain centre

The ________ is activated when the temperature of the blood changes and send impulses through the autonomic motor neurons to effectors in the skin and muscles.

positive feedback

The action of neurons also involves ________ with an influx in sodium ions depolarising the cell, causing voltage- gated sodium ion channels to open.

Contact dependent communication

________ may occur between signalling molecules in the plasma membrane of the signalling cells and receptor proteins present in the plasma membrane of the target cell.

sensory receptors

When the effector brings about a response that reverses the initial change in conditions, the system moves closer to the optimum, this is detected by ________ and the stimulus is reduced.

Homeostasis

________ is the maintenance of a constant internal environment despite changes in external and internal factors- CO2 concentration, body temperature, blood glucose, salt, and water potential, as well as pressure must be maintained within a small range of variables.

Communication systems

________ are needed to maintain the constant internal environment in a changing external environment.

Ectotherms

________ increase their body temperature through conduction by pressing their bodies against warm ground.

Environmental change

________ is stimulus, and the way organism changes its behaviour or physiology is the response.

hormonal system

The ________ uses the blood to transport chemical signals.

precapillary sphincters

If the body is too cold, less sweat is secreted to reduce heat lost in evaporation, hairs and feathers stand erect to create a layer of insulative air, and vasoconstriction of arterioles and ________ diverts blood away from the skin, reducing the amount of heat radiated from the body.

peripheral

Being the ________ and the largest organ, the skin has a number of physiological responses.

physiological responses of endothermic thermoregulation

The ________ are the result of homeostatic mechanisms using negative feedback control from the hypothalamus.

Cells

________ in endocrine glands release a hormone directly into the blood and it is transported throughout the body, but it only recognised by target ________ with the complementary cell- surface receptors to the shape of the signalling molecule.

Endotherms

________ control their body temperature within a small range of variables, largely independent of external temperatures, using their internal exothermic metabolic activities to keep them warm, and energy- requiring physiological responses to cool them down.

positive feedback

Conversely, ________ is where occurs where a deviation increases the original deviation, so is a mechanism whereby a change is increased.

sensory receptors

The interaction between ________, the autonomic nervous system and effectors helps ectotherms maintain a stable core body temperature despite a changing external environment.

hormonal system

The ________ enables longer- term responses to be coordinated.