Regulatory Systems Flashcards
Describe the relationship of size to thermoregulation?
- Smaller: have higher metabolism to keep warm, lose more heat due to large surface area
- Larger: have lower metabolic rate, retain heat better due to higher volume, little insulation, can overheat
How does temperature effect chemical reactions?
- Reactions occur quicker at higher temperatures
- The effect of temperature is mainly on enzymes
Describe the regulation of body temperature?
-Body temp is determined by: internal factors (ex. metabolism), external factors that affect heat transfer, behavior
What is body heat?
- It is the heat produced + heat transferred
- Heat transferred can be positive or negative (used for both heating or cooling)
What are the four mechanisms of heat transfer?
- Radiation: by electromagnetic radiation
- Conduction: directly between two objects
- Convection: by movement of a gas or liquid
- Evaporation: conversion of water to gas
What is thermogenesis?
- Use of energy to acquire heat
- Occurs when temperatures fall below a threshold
- Can occur through: changing the chemical composition of cells/tissues, altering the metabolism to produce heat, and shivering
How to plants respond to chilling?
- Increase the number of unsaturated lipids in their plasma membrane
- Limit the ice crystal formation to extracellular spaces
- Produce antifreeze proteins
- Some can undergo supercooling (survive temps as low as -40 celsius)
How do plants respond to high temperatures?
- Heat shock proteins if exposed to rapid temp increase
- Thermotolerance: plants can survive otherwise lethal temps if they’re gradually exposed to the increasing temps.
How is body heat generated?
- Warm blooded endotherms: use metabolism to generate body heat and maintain temp above ambient temp.
- Ectotherm: don’t use metabolism to produce heat and have body temp that conforms to ambient temp
- Homeotherms, heterotherms, and poikilotherms
Describe Ectotherms?
- Cold blooded
- Produce no heat (low metabolic rates)
- Have advantage of low energy intake
- Not capable of sustaining high energy activity
- Must regulate temp using behavior
Describe Endotherms?
- Produce heat (high metabolic rate)
- Allow for sustaining high energy activity
- Requires constant and high energy intake
- Can increase metabolism
- Need insulation
- Sweating or panting causes evaporation cooling
- Vasodilation increases blood flow (increases heat dissipation)
- Vasoconstriction decreases blood flow (limits heat loss)
What controls body temperature?
- Pyrogens: cause rise in temperature (act on hypothalamus to increase normal set point to higher temp which produces a fever)
- Torpor: state of dormancy, causes a reduction in metabolic rate and temperature
What are essential nutrients?
- Substances that an animal can’t manufacture itself but is necessary for its health
- Includes vitamins, amino acids, minerals, etc
What are the types of digestive systems?
- Single celled organisms/sponges digest food intracellularly (each cell digests for itself, no digestion in body cavity)
- Other multicellular animals digest food extracellularly (in digestive cavity)
- Specialization occurs when the digestive tract has a separate mouth and anus
What happens with ingested food?
- Subjected to physical fragmentation
- Stored
- Chemically digested (hydrolysis reactions break food into subunits)
- Absorption through epithelial lining into blood
- Wastes secreted from anus
Describe vertebrate digestive systems?
-Digestive system consists of a tubular gastrointestinal tract
Mouth and pharynx (entry)
Esophagus (delivers food to stomach)
Stomach (Preliminary digestion)
Small intestine (Absorption)
Large intestine (concentration of wastes)
Cloaca or rectum (waste storage and elimination)
What are the accessory organs of the vertebrate digestive system?
- Salivary glands (produce saliva)
- Liver (produces bile)
- Gallbladder (stores and concentrates bile)
- Pancreas (produces pancreatic juice and biocarbonate buffer)
What are the layers of the GI tract?
- Mucosa: epithelium that lines the interior, or lumen, of the tract
- Submucosa: connective tissue
- Muscularis: double layer of smooth muscles
- Serosa: epithelium that covers the external surface tract
Describe teeth?
- Used for acquiring food and processing it (mastication)
- Adapted to nutritional source (carnivores have teeth for puncturing and shearing, herbivores have large flat grinding teeth, humans have both)
What happens if they don’t have teeth?
- They break up food with a two chambered stomach
- It is a muscular chamber that uses ingested pebbles to pulverize food
Describe saliva?
- Tongue mixes food with saliva
- Contains salivary amylase which breaks down starch
- Salivation controlled by nervous system
Describe venom?
- Toxin
- subdues or kills prey
- evolved from modified salivary glands
How does swallowing work?
-When food is ready to be swallowed:
Tongue moves it to the back of the mouth
Soft palate seals off nasal cavity
Elevation of the larynx pushes the glottis against the epiglottis
Keeps food out of respiratory tract