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
Describe absorption?
- Amino acids and monosaccharides are transported through epithelial cells to blood
- Fatty acids and monoglycerides diffuse into epithelial cells
Describe wastes?
- Waste material is usually concentrated
- Water is reabsorbed before defecation
- Most mammals have a rectum
- Other vertebrates and monotremes have a cloaca where urinary, reproductive and gastrointestinal tracts join
What are different types of digestive systems?
- Ruminants: have four chambered stomach (rumen, reticulum, omasum, abomasum)
- Rumen has cellulose degrading microbes
- Horses, rabbits and deer digest cellulose in the cecum. These mammals practice coprophagy which is when they eat their feces to absorb more nutrients
Describe gas exchange?
- It’s dependent on surface area
- Smaller organisms do not need specialized breathing structures but instead exchange gas through skin
- Larger organisms have lungs or gills which add to surface area
How do single celled organisms breath?
- Gases diffuse directly through the membrane
- There is a high surface area to volume ratio
How do small invertebrates breath?
- Gases diffuse through integument and gut
- Flattening increases the surface area
ex. cnidarians, platyhelminthes, nematoda
How do larger invertebrates breath?
- Aquatic groups have internal gills
- Water is taken in and circulated over them and gas is exchanged
ex. mollusks and crustaceans
How do Echinoderms breath?
- Papulae protrude into water column (increase surface area)
- Oxygen is then circulated through the animal via the water vascular system
How do Insecta breath?
- Spiracles (openings in exoskeleton) lead to ducts called trachea
- These subdivide into tracheoles
How do Amphibians breath?
- Thin, moist skin with lots of capillaries allows for gas exchange
- Called cutaneous respiration
- Most do this but also need gills/lungs in addition
How do aquatic vertebrates breath?
- Derived from pharyngeal slits
- Several gill arches on each side of the animals head and each is composed of two rows of gill filaments which consist of lamellae
- External gills are outside the body (rare) - cons are they must move constantly to get O2 and they’re easily damaged
Where are the gills of bony fish located?
- Between the mouth and operculum
- Moves water through mouth, through gills, and out of the fish through the open operculum or gill cover
What is countercurrent flow?
- In aquatic vertebrates
- Blood flows opposite to the direction of water movement
- This maximizes the oxygenation of the blood
Why were gills replaced with lungs in terrestrial vertebrates?
- Air is less supportive than water
- They’d need a structure to retain moisture if gills were kept
How do terrestrial vertebrates breath?
- Lungs of amphibians are formed as saclike outpouchings of the gut
- Positive pressure breathing: push or squeeze air into lungs
- Negative pressure breathing: expand thoracic cage by muscular contractions creating empty space which air rushes into lungs to fill
- Lung are packed with alveoli
How does air enter the lungs?
- Inhaled air passes through trachea
- Bifurcates into the right and left bronchi
- Enter each lung and subdivide into bronchioles
What is unidirectional breathing?
- Instead of air going in and out the exact same way, air circulates
- Results in complete elimination of used air
- 2 cycles:
1. inhaled air is drawn from the trachea into posterior air sacs and exhaled into lungs
2. air is drawn from the lungs into anterior air sacs and exhaled through the trachea - Deoxygenated air doesn’t need to be exhaled before oxygenated air can be inhaled
Describe hemoglobin?
-Consists of four polypeptide chains Each chain is associated with a heme group Each heme group has an iron atom Iron can bind a molecule of O2 -One hemoglobin can carry four O2 atoms
Which way does the xylem transport?
-Unidirectionally (up the plant)
Describe Phloem transport?
- Most carbohydrates that are produced in the leaves are distributed through the phloem to the rest of the plant
- The nutrient rich fluid is sap
- Sucrose is transported up and down the phloem
- It makes sugar in the leaves then transports it down
What is the pressure flow theory?
- Dissolved carbohydrates flow from a source and are released at a sink
- Sources include photosynthetic tissues
- Sinks include growing root and stem tips well as developing fruits
Describe phloem loading?
- Occurs at the source:
1. Mesophyll makes sugars
2. Active transport of sugars into phloem causes low water potential
3. Turgor pressure increases in phloem
4. This increased pressure drives the contents to the sink
5. Once at the sink, sugar is then actively transported into cells that need it
6. Water diffuses back into the xylem to be reused
Describe the invertebrate circulatory system?
- Sponges, cnidarians and nematodes lack separate circulatory system (no circulatory system)
- Carry oxygen throughout by having smaller size which allows for diffusion
- Other animals require separate circulatory system: Open circulatory system - there is a circulatory system but allows for more mixing of oxygenated and deoxygenated which is not as efficient
- Other animals require separate circulatory system: Closed circulatory system - Distinct circulatory fluid enclosed in vessels and transported away from and back to the heart
Describe fish circulation?
- Path of blood: body, heart, gills, body
- 2 chambered heart
- Fish evolved the first chamber-pump heart
- Ventricle has more muscle tissue
- Four structures are arranged to form two muscular pumping chambers
- One atrium and one ventricle
Describe land vertebrate circulation?
- Lung requires a second pumping circuit or double circulation
- Pulmonary circulation: goes to lungs (heart, lungs, heart)
- Systemic circulation: goes to body (heart, body, heart)
Describe amphibian/reptile circulation?
- Three chambered heart
- Two atria, one ventricle
- Oxygenated and deoxygenated blood mix
Describe mammal/archosaur circulation?
- Four chambered heart
- two separate atria, two separate ventricles
- oxygenated and deoxygenated do not mix
How does blood flow through vessels?
- Blood leaves the heart through the arteries
- Arterioles are the finest, microscopic branches of the arterial tree
- Blood from arterioles enters capillaries
- Artery has much thicker muscle
- Blood is collected into venules
- Venules lead to larger vessels, veins carry blood back to heart
- Capillaries connect to venules, venules connect to veins (veins have much less muscle than arteries do and have valves which regulate blood flow)
What are characteristic of large vessels?
-Arteries and veins are composed of four tissue layers Endothelium Elastic fibers Smooth muscle (involuntary) Connective tissue
Describe capillaries?
-Composed of a single layer of endothelial cells
What are the functions of circulating blood?
- Transportation of materials
- Regulation of body functions
- Protection from injury and invasion
Describe plasma?
- Matrix
- Mainly water
- Also nutrients, wastes, hormones, ions, proteins
- If removed plasma is called serum
Describe red blood cells?
- AKA erythrocytes
- Red blood cells of vertebrates contain hemoglobin
- Carry oxygen
Describe white blood cells?
- AKA leukocytes
- Have nuclei and are larger than erythrocytes
- Can migrate out of capillaries
- Immune response
Describe platelets?
- Are cell fragments that pinch off from larger cells in the bone marrow
- Function in the formation of blood cells
What is hematopoiesis?
-Blood cell production
