Internal Environments and Temperature Effects ( Lecture 2)

Flashcards reviewing regulatory systems, feedback mechanisms, tissue types, temperature effects on organisms, and methods of heat exchange.

What are regulatory systems?

The combination of the nervous and endocrine systems, exemplified by a thermostat.

What are controlled systems?

All other bodily systems affected by the nervous and endocrine systems.

Give an example of a positive feedback system.

Childbirth and the opening of the cervix.

Give an example of feed foreward feedback.

Increased saliva production when smelling food.

Why don't cells function well below 32 degrees Fahrenheit?

Cells function poorly below this temperature because water freezes and expands, causing cells to explode.

Why don't cells function well above 40 degrees centigrade/104 degrees Fahrenheit?

Cells don't function well above this temperature because proteins begin to unravel or denature.

What are redox reactions?

Reactions where electrons are transferred between compounds.

How are biochemical reactions linked in the body?

The product of one reaction becomes the reactant for the next.

What happens when you increase the temperature often to reactions?

The rate at which a reaction occurs.

What is the Q10 value?

The sensitivity of a particular reaction to a change in temperature.

If the Q10 is two, what happens for every 10-degree change in temperature?

For every 10-degree change, the reaction rate will double.

What are ectotherms?

Organisms whose body temperature is determined by outside sources of heat.

Give examples of ectotherms.

Lizards, snakes, and insects.

What are endotherms?

Organisms that can regulate their internal temperature by producing their own heat through metabolism.

Give an example of endotherms.

Mammals and birds.

What are heterotherms?

Organisms that can behave as an ectotherm or an endotherm at different times.

What is the body temperature of endotherms?

As the environmental temperature increases, body temperature stays the same.

What is the thermal neutral zone?

A range where, given the ambient temperature, an organism's body doesn't have to do a lot to maintain its temperature.

What is radiation?

Heat transfer via infrared radiation or infrared energy.

What is convection?

Heat transfer through surrounding medium.

What is conduction?

Heat transfer by direct contact.

What is evaporation?

Heat loss through water evaporation.

What is thick fur?

Animals that live in cold environments have this to maintain heat.

What are vasoconstriction and vasodilation?

The ability to direct blood either towards or away from the skin depending on conditions.

What is energy budget?

A balance between heat produced/absorbed and heat lost.

What is basal metabolic rate?

The absolute minimum energy needed to carry out normal everyday functions.

What is daily torpor?

Ability to lower temperature and metabolic rate during inactive periods.

What is hibernation?

Ability to drop body temperature and metabolic rate for days or weeks.

What are endocrine cells?

Any cells that produce and release a chemical signal into the extracellular fluid (interstitial fluid or blood plasma).

What is a hormone?

A chemical signal released from an endocrine cell that enters the blood and activates a target cell further away.

What are paracrines?

Endocrine cells that secrete a chemical signal into the surrounding interstitial fluid only, triggering nearby cells.

What are autocrines?

An endocrine cell that secretes a chemical signal that affects another cell and itself.

What are exocrine glands?

They secrete their chemical solution/secretion to the outside or into a body cavity.

What are endocrine glands?

They secrete hormones or chemical signals into the extracellular fluid.

What do neurons/nerve cells do?

They communicate with other cells by secreting a neurotransmitter, usually active locally (paracrine).

What are neurotransmitters?

A hormone that are active locally (paracrine).

What are neurohormones?

Neurons can secrete chemical signals that enter the bloodstream and move further away.

What are peptides and protein hormones?

Hormones made up of proteins.

What are steroid hormones?

Estrogen and testosterone: They are liquids and don't like water.

What are amine Hormones?

Mostly amino acids that can be hydrophilic or hydrophobic.

What is epinephrine?

An amine hormone responsible for the fight or flight response.

What is prolactin?

A hormone with a similar structure across vertebrate groups, functioning differently but similarly in reproduction.