Midterm 1 Flashcards
What are the 6 basic characteristics of animals?
1) Multicellular
2) Heterotrophic
3) Eukaryotic
4) Motile
5) No cell wall
6) Go through blastula
How can animals characterized?
By body plans
How many identified living species of animals are there?
1.3 Million
What are heterotrophs?
Obtain organic molecules from their food that they ingest and digest within their bodies
What are 2 defining characteristics of animals?
1) Nervous tissue
2) Muscle tissues
Definition of tissues
Groups of cells that act as a functional unit
What do parazoans lack?
They have no true tissue
What is the group called for all animals?
Metazoa
What does the group eumetazoa mean?
Animals w/ specialized tissues
How do zoologists sometimes categorize animals by?
Body plan: a set of morphological and developmental traits
How long has the molecular control of gastrulation remained unchanged?
More than 500 million years
What are the 4 characteristics of bilaterally symmetrical animals?
1) Dorsal and ventral (top and bottom)
2) right and left
3) Anterior and posterior (front and back)
4) cephalization: brain
True or False: Bilateral animals are triploblasts and Radial animals are diploblasts?
TRUE
What are the 5 stages of early embryonic development in animals?
1) zygote
2) 8-cell stage
3) Blastula
4) Gastrulation
5) Gastrula
What stage usually dominates the life cycle (diploid or haploid)?
Diploid stage
What are the 3 layers in tissue from outermost to innermost (triploblastic)?
1) Ectoderm
2) Mesoderm
3) Endoderm
What layer of tissue do diploblasts lack?
Mesoderm
Which animal is considered to be the simplest?
Trichoplax adhaerens (TP); used to be th only living species in the phylum placozoa (now there are 4)
What is a pseudocoelom?
A body cavity derived from mesoderm and endoderm (only triploblasts). Animals that possess these are called pseudocoelomates
Triploblastic animals that lack a body cavity are called what?
Acoelomates
What are triploblasts that contain a true coelom called?
Coelomates
True or false: radial cleavage leads to protostomes and spirall cleavage leads to deuterostomes
False: spiral cleavage = protostomes & radial cleavage = deuterostomes
What are ecdysozoans?
Invertebrates that shed their exoskeleton through a process called ecdysis
What does arthropod mean?
Jointed feet
Most animals, and only animals have these types of genes, what are they?
Hox genes: highly conserved and it can produce a wide diversity of animal morphology
What animal most resembles the closest living relative to animals?
Choanoflagellates: protists that are closest living relatives of animals
How long ago did the common ancestor of all living animals live between?
700-770 MYA
What are the 3 forms of evidence that choanoflagellates are closely related o animals?
1) Cell morphology
2) Cell morphology unique to animal cells
3) DNA sequence homology
What is anatomy?
It’s the biological form of an organism
What is physiology?
The study of biological functions an organism performs
How does a jackrabbit keep from overheating?
Their hug are ears help them regulate their body heat by increasing or decreasing blood flow through their ears
What 2 characteristics affect the way an animal interacts w/ its env?
1) size
2) shape
What is the body plan of an animal programmed by?
It’s programmed by the genome
What are the 4 things physical laws constrain?
1) strength
2) diffusion
3) movement
4) heat exchange
As animals increase in size what needs to happen?
Their skeletons must be proportionally larger to support their mass
What does evolutionary convergence reflect?
It reflects how adaptations are similar due to similar environmental challenges
What is the rate of exchange of nutrient, waste products, and gases across cell membrane proportional to?
Rate of exchange is proportional to a cell’s surface area
What is the amount of exchange material proportional to?
Amount of exchange material is proportional to a cell’s volume
What are the 4 internal exchange surfaces of complex animals?
1) Digestive system
2) Circulatory system
3) Respiratory system
4) Excretory system
(Digestive system) What characteristic of the small intestines aid in exchange?
The lining of the small intestine has finger-like structures that expand the surface area for nutrient absorption
(Excretory system) What characteristics of the kidneys aid in exchange?
Blood is filtered across the surface of long, narrow blood vessels packed into ball-shaped structures
(Respiratory system) What characteristics of the lungs aid in exchange?
They are sponge-like and balloon-like which provides an expensive wet surface for gas exchange w/ the env
In vertebrates, what fluid fills the space b/w cells, and what does this fluid allow for?
Interstitial fluid which allows for the movement of material into and out of cells
How does a complex body plan help animals?
It helps with living in variable envs to maintain a relatively stable internal env
What is the order of the hierarchical organization of body plans?
Specialized cells -> tissues -> organs -> organ systems
What is an example of an organ that belongs to more than one organ system?
Pancreas
What are the 4 main categories of tissues?
1) Epithelial
2) Connective
3) Muscle
4) Nervous
Where is epithelial tissue found?
It cover the outside of the body and lines organs and cavities within the body and contains cells that are closely joined
What are the 3 shapes of epithelial cells?
1) cuboidal
2) columnar
3) squamous
What are the 3 arrangements of epithelial cells?
1) simple: single cell layer
2) stratified: multiple tiers of cells
3) pseudo-stratified: a single layer of cells of varying length
What do connective tissues do?
It mainly binds and supports other tissues
What are the 3 types of connective tissue fibres (all made of protein)?
1) Collagenous fibres: strength + flexibility
2) Elastic fibres: stretch and snap back
3) Reticular fibres: join connective tissue to adjacent tissues
What are the 2 types of cells in connective tissues?
1) Fibroblasts: secrete the protein of extracellular fibres
2) Macrophages: are involved in the immune system
What are the 6 major types of connective tissue in vertebrates?
1) Loose connective tissue
2) Fibrous connective tissue
3) Bone
4) Adipose tissue
5) Cartilage
6) Blood
What is muscle tissue responsible for?
Nearly all types of body movement
What do muscle cells consist of?
Filaments of the protein actin and myosin which together enables muscles to contract in response to nerve signals
What are the 3 groups of muscle tissue?
1) skeletal
2) smooth
3) cardiac
What are the 2 things nervous tissue contains and what do they do ?
1) Neurons/nerve cells: transmit nerve impulses
2) Glial cells/glia: help nourish, insulate, and replenish neurons
What do control and coordination within the body depend on?
They depend on the endocrine system and the nervous system
True or false: hormones act relatively slow, but can have long-lasting effects?
True
The information conveyed in the nervous system depends on what?
the information converted depends on a signal’s pathway, not the type of signal
Is neuron signal transmission fast or slow?
Very fast
What do regulators do?
They use internal control mechanisms to moderate internal change in the face of external environmental fluctuation
What do conformers do?
They allow their internal condition to vary with certain external changes
What do mechanisms of homeostasis do?
They moderate changes in the internal environment
What serves as stimulus in homeostasis?
For a given variable, fluctuations above or below a set point serve as a stimulus; these are detected by a sensor and trigger a response ad the response returns the variable to the set point
Is homeostasis a positive or negative feedback loop?
Negative feedback loop, since it returns a variable to a normal range
What do positive feedbacks do?
It amplifies a stimulus and doesn’t usually contribute to homeostasis in animals
Alterations in Homeostasis are caused by what?
Circadian Rhythm
Define acclimation?
Adjustment to a single environmental factor
Define acclimatization?
Adjustment to multiple factors
Define thermoregulation
The process by which animals maintain an internal temp within a tolerable range
How do endothermic animals generate heat?
Generate heat by metabolic activities; birds and mammals
How do ectothermic animals generate heat?
Gain heat from external sources; invertebrates, fishes, amphibians, and on avian reptiles
True or false: endotherms can’t maintain a stable body temp even in the face of large fluctuations in environmental temp
FALSE: they CAN maintain a stable body temp even in the face of large fluctuations in env temp; requires a lot of energy
True or false: in general, ectotherms tolerate greater variation in internal temps?
True
What are the 4 physical processes animals use to exchange heat?
1) Radiation
2) Evaporation
3) Convection
4) Conduction
What system in mammals is often involved in heat regulation?
integumentary system: skin, hair, and nails
What are 5 adaptations evolved to help animals thermoregulate?
1) Insulation
2) Circulatory adaptations
3) Cooling by evaporative heat loss
4) Behavioural responses
5) Adjusting metabolic heat production
What is the circulatory adaptation that marine mammals and birds evolved?
The arrangement of blood vessels in many marine mammals and birds allows for countercurrent exchange
What is countercurrent exchange?
Countercurrent heat exchangers transfer heat b/w fluids flowing in opposite directions and thereby reducing heat loss
How do many animals lose heat?
Through evaporation of water from their skin since sweating or bathing moistens the skin, helping to cool an animal down. Panting also increases the cooling effect in birds and many mammals
What behaviour by terrestrial invertebrates is used to minimize or maximize solar heat absorption?
They have postures that minimize or maximize absorption of solar heat
What behaviours in honey bees allows them to retain heat?
They huddle together during cold weather to retain heat
What is the definition of thermogenesis?
It’s the adjustment of metabolic heat production to maintain body temp
How is thermogenesis increased?
It’s increased by muscle activity such as moving or shivering
What is nonshivering thermogenesis (NST)?
it takes place when hormones cause mt to increase their metabolic activity
What is Brown Adipose Tissue (BAT) implicated in?
Burns energy to produce heat
What do ectotherms produce when temperatures are subzero and what does it do?
They produce “antifreeze” compounds to prevent ice formation in their cells
What region of the brain in mammals controls thermoregulation?
Hypothalamus; it triggers heat loss or heat generating mechanisms
What is bioenergetics?
the overall flow and transformation of energy in an animal
What does bioenergetics determine in animals and what does it relate to?
determines how much food an animal needs, and it relates to an animal’s size, activity and env
What is metabolic rate?
It’s the amount of energy an animal uses in a unit of time
What are the 3 things metabolic rate is determined by?
1) An animal’s heat loss
2) The amount of oxygen consumed or CO2 produced
3) Measuring energy content of food consumed and energy lost in waste products
What is the Basal metabolic rate (BMR)?
the metabolic rate of an endotherm at rest at a “comfortable” temp
What is the Standard metabolic rate (SMR)?
the metabolic rate of an ectotherm at rest at a specific temp
What 3 things do BMR and SMR both assume?
assume a nongrowing, fasting, and non-stressed animal
True or false: Ectotherms have much higher metabolic rates than endotherms of a comparable size
FALSE: Ectotherms have much lower metabolic rates than endotherms of a comparable size
What are 6 key factors that affect metabolic rates?
1) age
2) sex
3) size
4) activity
5) temp
6) nutrition
What is metabolic rate proportional to?
Metabolic rate is proportional to body mass to the power of 3/4 (m^3/4). Smaller animals have higher metabolic rates per gram than larger animals
What is torpor and what does it enable?
It’s a physiological state in which activity is low and metabolism decreases and it enables animals to save energy while avoiding difficult and dangerous conditions
What is hibernation?
It’s long-term torpor, that is an adaptation to winter cold and food scarcity
What is the name of summer torpor and what does it enable?
It’s called estivation and it enables animals to survive long periods of high temps and scarce water
Who exhibits daily torpor and what is it adapted to?
Daily torpor is exhibited by many small mammals and birds and seems adapted to feeding patterns
What 3 things do feedback circuits regulate?
1) digestion
2) energy storage
3) appetite
What is dentition in mammals specialized for?
different diets
What are the 4 classes of essential nutrients?
1) Essential amino acids
2) Essential Fatty acids
3) Vitamins
4) Minerals
What do micronutrients play roles in?
they play roles in enzyme function as substrates, coenzymes, and cofactors
How many amino acids do animals require and how many can they synthesize?
Require 20 and can synthesize about half and the remaining essential amino acids must be obtained from food
What 3 foods provide all essential amino acids and thus “complete” proteins?
1) meat
2) eggs
3) cheese
How do animals obtain essential fatty acids (can’t synthesize them)?
must be obtained from the diet and include unsaturated fatty acids (one or more double bonds).
True or false: Deficiencies in fatty acids are rare
TRUE
How many vitamins are essential for humans and what are the 2 groups that they fall under?
13 and they are grouped into 2 categories: Fat-soluble and water-soluble
What is scurvy?
a severe vitamin C deficiency
Which 5 fruits have the top highest vitamin C levels?
1) Guavas
2) Kiwifruit
3) Bell peppers
4) Strawberries
5) Oranges
What is the current daily value for vitamin C?
90mg
What is Hematomacrosis?
Causes Fe buildup without excessive Fe intake
VITAMINS (B9 onwards):
1) B9 = folic acid
2) B12 = cobalamin
3) C = ascorbic acid
4) A = Retinol
5) E = tocopherol
6) K = phylloquinone
How do cattle, deer and other herbivores prevent phosphorous deficiencies?
They consume concentrated sources of salt or other minerals; licking rocks or the ground
What are the 5 things that undernourished individuals will do?
1) use up stored fat and carbs
2) break down its own proteins
3) lose muscle mass
4) suffer protein deficiency of the brain
5) die or suffer irreversible damage
What are the 4 main ways of feeding?
1) Suspension feeding
2) substrate feeding
3) fluid feeding
4) bulk feeding
How do suspension feeders obtain their food?
Many aquatic animals are suspension feeders which sift small food particles from the water. Example = whales w/ baleen
How do substrate feeders obtain their food?
They are animals that live in or on their food. Example = caterpillars
How do fluid feeders obtain their food?
They suck nutrient-rich fluid from a living host. Example = black soldier fly which sucks nectar from flowers
How do bulk feeders obtain their food?
They eat relatively large pieces of food. Example = Lions, snakes, etc.
In enzymatic digestion, what does enzymatic digestion do?
It split bonds in molecules with the addition of water
Define elimination in the context of digestion?
Elimination is the passage of undigested material out of the digestive system
Most animals process foods in specialized compartments, why is this?
It reduces the risk of an animal digesting its own cells and tissues
What is intracellular digestion and give an example of an organism that digests through this process?
Food particles are engulfed by phagocytosis. Example = sponges digest their food entirely by this mechanism
Animals have. Digestive tube with 2 openings, mouth and anus, what is this digestive tube called?
Complete digestive tract or an alimentary canal
What does the mammalian digestive system consist of (2)?
1) an alimentary canal
2) accessory glands that secrete digestive juices through ducts
What are the 4 mammalian accessory glands that secrete digestive juices through ducts?
1) The salivary gland
2) The pancreas
3) The liver
4) The gallbladder
How is food pushed along during digestion?
It’s pushed along by peristalsis, rhythmic contractions of muscles in the wall of the canal
What regulates movement of material b/w compartments in digestion?
Vives called sphincters
What does the first stage of digestion consist of?
Occurs in the oral cavity where salivary glands deliver saliva to lubricate food, teeth chew food into smaller particles to then be mixed w/ salivary amylase which initiates breakdown of glucose polymers
What does saliva also contain and what is this made of?
Saliva also contains mucus which is a viscous mixture of water, salts, cells, and glycoproteins
What shape does the tongue shape food into?
The tongue shapes food into a bolus and helps with swallowing
Where does the pharynx (the throat) lead to?
The throat, or pharynx, is the junction that opens to both the esophagus and the trachea.
What part connects to the stomach?
The esophagus connects to the stomach
What part blocks entry to the trachea?
Swallowing causes the epiglottis to block entry to the trachea which lead to the lungs
When does coughing occur when you’re eating food?
Coughing occurs when the swallowing reflex fails and food or liquid reach the windpipe
The stomach secretes gastric juices which converts a meal into what?
Your meal becomes chyme
What is the pH of gastric juices and what does it do?
has a low pH of 2 which kills bacteria and denatures proteins
What are the 2 components of gastric juice?
1) HCl
2) Pepsin - protease that cleaves proteins into smaller peptides
What do parietal cells in the stomach do?
They secrete H+ ad Cl- separately into the stomach lumen
What do chief cells secrete into the stomach?
They secrete inactive pepsinogen which is activated when mixing w/ HCl = pepsin
What protects the stomach lining from gastric juices?
Mucus
What bacteria mainly causes gastric ulcers and lesions in lining?
Helicobacter pylori
What is the longest section of the alimentary canal and is the site of most enzymatic hydrolysis of macromolecules from food?
The small intestine
What is the first portion of the small intestine and what does it do?
The duodenum = were chyme from stomach mixes w/ digestive juices from the pancreas, liver, gallbladder, and small intestine itself
What does the the pancreas secrete and what does it do to the acidic chyme?
The pancreas produces trypsin and chymotrypsin that are activated in the lumen of the duodenum and this solution is alkaline and so it neutralizes the acidic chyme
Where is bile made, where is it stored and what does it aid in?
Bile is made in the liver an stored in the gallbladder and in the small intestine it aids in digestion and absorption of fats
What’s an additional function of bile in accordance w/ red blood cells?
Bile also destroys nonfunctional red blood cels
What part of the duodenum produces several digestive enzymes?
Epithelial lining of the duodenum
Where does the most digestion occcur?
In the duodenum; the jejunum and ileum function mainly in absorption of nutrients + H2O
How does the small intestine have a huge surface area and what does this create?
Huge surface area due to villi and microvilli which creates a brush border that greatly increases rate of nutrient absorption
What does the cecum aid in and where does it connect?
The cecum aids in the fermentation of plant material and connects where the small intestine and large intestine meet
What is an extension of the cecum in humans?
The appendix, which plays a minor role in immunity
What is the major function of the colon?
Recover water that has entered the alimentary canal
Why do herbivores and omnivores have longer alimentary canals than carnivores?
It reflects the longer time needed to digest vegetation; need longer cecum which aids in the fermentation of plant material
What 2 hormones regulate the breakdown of glycogen into glucose?
Insulin and glucagon
What organ is the site for glucose homeostasis and which hormones increase and decrease glucose levels?
The liver; insulin decreases glucose, glucagon increases it
What is partial pressure?
The pressure exerted by a particular gas in a mixture of gases
What are gills?
Outfoldings of the body that create a large surface area fo gas exchange
What kind of exchange is demonstrated by Gills?
Countercurrent exchange
What does the tracheal system of insects consist of?
A network of branching tubes throughout the body
What 2 characteristics of the lungs correlate with an animal’s metabolic rate?
1) size
2) complexity
-> Of the lungs
What are lungs?
Infolding of the body surface
What is the order that air passes through in the mammalian respiratory system?
1) pharynx
2) larynx
3) trachea
4) bronchi
5) bronchioles
6) alveoli = where gas exchange occurs
Where in the mammalian respiratory system does gas exchange occur?
Alveoli
How does an amphibian breath?
Amphibians such as frogs ventilate their lungs by positive pressure breathing which forces air down the trachea
How do mammals breath?
They ventilate their lungs by negative pressure breathing which pulls air into the lungs
What is the term for the volume of air inhaled w/ each breath?
Tidal volume
What is maximum tidal volume?
Vital capacity
Where is the breathing control center located in humans?
It’s located in the medulla oblongata of the brain which regulates rate and depth of breathing in response to pH changes in cerebrospinal fluid
Where in vertebrates is hemoglobin contained within and how many molecules of oxygen can each hemoglobin carry?
It’s contained within erythrocytes, and a single hemoglobin can carry 4 O2 molecule = 1 per iron containing heme group
Where is oxygen stored in diving mammals?
They can store O2 in their muscles in myoglobin proteins
What are 3 ways diving mammals can conserve oxygen?
1) changing their buoyancy to glide passively
2) decreasing blood supply to muscles
3) deriving ATP in muscles from fermentation once O2 is depleted
What are the functions of gastrovascular cavities in some cnidarians, such as jellies?
functions in both digestion and distribution of substances throughout the body
What are the 3 main components of a circulatory system?
1) circulatory fluid
2) set of interconnecting vessels
3) muscular pump = heart
What is an open circulatory system?
There is no distinction b/w blood and the interstitial fluid (hemolymph)?
Do insects, other arthropods, and most molluscs have an open or closed circulatory system?
Open: circulatory fluid called hemolymph bathes organs directly (no distinction b/w interstitial fluid and blood)
What is a closed circulatory system?
Blood is confined to vessels and is distinct from the interstitial fluid; they’re more efficient at transporting circulatory fluids to tissues and cells
What 3 groups of organisms have closed circulatory systems?
1) Annelids
2) Cephalopods
3) Vertebrates
What is the name of the circulatory system in humans and other vertebrates? AND what are the 3 types of blood vessels?
Cardiovascular system
Blood vessels:
1) arteries
2) veins
3) capillaries
Is blood flow in the cardiovascular system 1 way or 2 way?
1 way blood flow
What is the order that blood circulates in the vertebrate circulatory system?
Heart -> Arteries -> arterioles -> capillaries -> capillary beds -> Venules -> veins -> Heart
Capillary beds are the sites of what?
Chemical exchange b/w blood and interstitial fluid
Bony fish, rays, and sharks have what kind of circulation with a heart with how many chambers?
Single circulation w/ 2 chambered heart
In single circulation, how many capillary beds does the blood pass through before returning to the heart?
Blood passes through 2 capillary beds before returning
What happens in double circulation which occurs in other vertebrates?
Oxygen-poor blood and oxygen-rich blood are pumped separately. Oxygen-rich blood is delivered from the heart to the rest of the body through the systemic circuit.
Through wat circuit does oxygen-rich blood travel through from the heart to the rest of the body?
The systemic circuit
Through what circuit does blood travel from the heart to the respiratory surface?
Pulmonary circuit
How many chambers are there in the heart of frogs and other amphibians and what circuit does oxygen-poor blood travel through?
They have a 3 chambered heart (2 atria + 1 ventricle) and oxygen-poor blood travels through a pulmocutaneous circuit to pick up O2 through lungs and skin
What happens to the blood flow in amphibians when they’re underwater?
Blood flow to the lungs is nearly shut off
What kind of circulation do reptiles have and what are the 2 circuits that their blood goes through?
Reptiles have double circulation w/ a pulmonary circuit (lungs) and a systemic circuit
What is different about snakes, lizards and turtles when talking about circulation and blood flow?
The one ventricle is partially divided by an incomplete septum
What is different about crocodilians when talking about circulation and blood flow?
A septum divides te ventricle, but pulmonary and systemic circuits are connected where arteries exit the heart
In mammals and birds, how many chambers does their heart have?
4 chambered heart = 2 ventricles and 2 atria
In mammals and birds, which side of te heart only pumps and receives oxygen-rich blood and which side only pumps and receives oxygen-poor blood?
Left = only rich blood
Right = only poor blood
What kind of circulation do mammals have and what is different about it?
They have double circulation where pulmonary and systemic blood are completely separate; the heart is separated into 2 ventricles
In the mammalian heart, what do the atria serve as?
The 2 atria have relatively thin walls and serve as collection chambers for blood returning to the heart
In the mammalian heart, what do the ventricles serve as?
The ventricles have thicker walls and contract much more forcefully
What rhythmic cycle does the heart follow?
Cardiac cycle
What is the name of the contraction, or pumping phase called during the cardiac cycle?
Systole
What is the name of the relaxation phase or filling stage of the cardiac cycle?
Diastole
What is the definition of heart rate?
Also called pulse, is the # of beats per minute
What is the definition of stroke volume?
The amount of blood pumped in a single contraction
What is the definition of cardiac output?
The volume of blood pumped into the systemic circulation per minute and depends on both heart rate and stroke volume
What do the atrioventricular valves (AV) separate in the heart?
They separate each atrium and ventricle
What do the semilunar valves control?
They control blood flow through to the aorta and the pulmonary artery
What mechanisms regulate arterial blood pressure by altering te diameter of arterioles?
Homeostatic mechanisms;
1) Vasoconstriction: contraction of smooth muscle in arteriole walls; it increases blood pressure
2) Vasodilation: relaxation of smooth muscles in the arterioles; it causes blood pressure to fall
What is healthy blood pressure in a 20 yr old?
120mmHg systole and 70mmHg diastole
True or false: animals with long necks require a very high systolic pressure to pump blood a greater distance against gravity
TRUE
What is one type of cardiovascular disease caused by the buildup of fatty deposits (plaque) within arteries?
Atherosclerosis
What is another name for a heart attack and what is it caused by?
Myocardial infarction is the damage or death of cardiac muscle tissue resulting from blockage of one or more coronary arteries which supply oxygen-rich blood to the heart
What is a stroke caused by?
It’s the death of nervous tissue in the brain, usually resulting from suture or blockage of arteries in the head
What are the 3 aspects of innate immunity in invertebrates?
1) Chitin exoskeleton = 1st barrier
2) Lysozyme, an enzyme that breaks down bacterial cell walls in digestive system
3) Hemocytes circulating within hemolymph and carry our phagocytosis
What is phagocytosis?
The ingestion and digestion of foreign substances including bacteria where a phagocytic cell engulfs the bacteria by endocytosis and the vacuole fuses w/ lysosome
How does the immune system recognize bacteria and fungi?
Recognizes them by structures on their cell walls
Insects also have specific defences against infection by viruses, how does t work?
The presence of RNA can trigger a specific defence against invading virus in insects
What are the 3 components of the innate immunity?
1) barrier defenses
2) phagocytosis
3) antimicrobial peptides
What are 3 additional defences unique to vertebrates?
1) natural killer cells
2) interferons
3) inflammatory response
What are the 4 barrier defenses?
1) Skin
2) Mucous membranes of the respiratory tract
3) Urinary tract
4) Reproductive tract
What aspect of the skin and digestive system prevents growth of many bacteria?
Low pH
How do phagocytic cells recognize groups of pathogens in innate defenses?
by TLRs, Toll-like receptors; TLRs recognize fragments of molecules characteristic of a set of pathogens
How do white blood cells work in innate defences
They engulf invading pathogens; the resulting vacuole containing the microbe fuses w/ a lysosome to destroy it
What are the 2 main types of phagocytic cells?
1) Neutrophils; engulf + destroy pathogens
2) Macrophages; found throughout body
What are 2 additional types of phagocytic cells?
1) Dendritic cells; stimulate development of adaptive immunity
2) Eosinophils; release destructive enzymes
What do natural killer cells do in innate defenses in vertebrates?
they circulate throughout the body and detect abnormal cells then they release chemicals leading to cell death, inhibiting the spread of virally infected or cancerous cells
What 2 things do interferon proteins provide during innate defense?
they interfere w/ viruses and help activate macrophages
What is the complement system of innate defense?
About 30 proteins that cause lysis of invading cells and helps trigger inflammation
What are mast cells and what do they do during the inflammatory response?
They are a type of connective tissue and they release histamines which triggers blood vessels to dilate and become more permeable
What do activated macrophages and neutrophils release?
Cytokines: signaling molecules that enhance the immune response
What is a fever and what is it triggered by?
It’s a systemic inflammatory response triggered by substances released by macrophages in response to certain pathogens
What is septic shock caused by?
It’s a life-threatening condition caused by an overwhelming inflammatory response
How do Pathogens evade innate immunity?
Some avoid destruction by modifying their surface to prevent recognition or by resisting breakdown following phagocytosis
What is one disease that evades innate immunity?
Tuberculosis (TB)
What are lymphocytes?
White blood cells
Are lymphocytes a part of innate immunity or adaptive immunity?
Both: do phagocytosis (innate) and B and T cells (adaptive)
What are lymphocytes called that mature in the thymus above the heart?
T cells
What are lymphocytes called that mature in bone marrow called?
B cells
What are antigens?
Substances that can elicit a response from B or T cells
How do T or B cells bind to antigens?
They bind via antigen receptors specific to that pathogen
What is the small accessible part of the antigen that the antigen receptor binds to?
Epitope
How do B and T cells differ?
They differ in how they encounter pathogens since their antigen receptors are different. B cells have Y shaped chain w/ an antigen receptor on either end and T cells at the tip of the chain have 1 antigen receptor shaped like a V
B cell activation gives rise to cells that secrete what?
B cell activation gives rise to plasma cells and they secrete a soluble form of the receptor called an antibody or immunoglobulin (Ig)
T cells bind to antigen fragments displayed or presented on a host cell. What molecules display these fragments?
MHC (major histocompatibility complex) molecules are host proteins that display antigen fragments on the cell surface
What do MHC molecules do in infected cells?
They bind and transport antigen fragments to the cell surface in a process called antigen presentation then a T cell can bind to both MHC and antigen fragment
What are the 4 major characteristics of the adaptive immunity system?
1) immense diversity of lymphocytes and receptors
2) Self-tolerance; lack of reactivity against an animal’s own molecules
3) B and T cells proliferate after activation
4) Immunological memory
When activated, a B or T cell undergoes clonal selection to produce a clone of identical cells. What are the 2 types of clones produced?
1) Effector cells: short-lived and act immediately against antigen
2) Memory cells: long-lived and can give rise to effector cells if the same antigen is encountered again
What are cytotoxic T cells?
effector cells in the cell-mediated immune response. They use toxic proteins to kill cells infected by viruses or other intracellular pathogens
The defenses provided by B and T lymphocytes can be divided into 2 different immune response, what are they?
1) humoral immune response
2) Cell-mediated immune response
What occurs in the humoral immune response?
involves the production of antibodies (also called immunoglobulins) that help neutralize or eliminate toxins + pathogens in the blood and lymph
What occurs in the cell-mediated immune response?
specialized T cells destroy affected host cells
What do helper T cells do?
bind to antigen and class II MHC molecule which then activates it. Then it forms clones which then activate the appropriate B cells
With the help of 2 things, B cells can proliferate and differentiate into memory B cells and plasma cells, what are these two things?
1) Cytokines from helper T cells
2) Antigen
What is immunization?
the use of antigens artificially introduced into the body to generate an adaptive immune response and memory cell formation
When does active immunity develop?
develops naturally when a pathogen invades and elicits primary or secondary immune response or it can develop following immunization (vaccination) where an antigen is introduced into the body
What does passive immunity provide and how is it produced artificially?
provides immediate, short-term protection. Can develop artificially when antibodies from an immune animal are injected into a non-immune animal
What are allergies?
exaggerated (hypersensitive) responses to antigens called allergens
What does osmoregulation balance?
the uptake and loss of water and solutes
What happens if two solutions on either side of a membrane differ in osmolarity?
Net flow is from the hypoosmotic (less concentrated) to the hyperosmotic (more concentrated) solution
How does water enter and leave the cell?
by osmosis
What is osmolarity? AND what does it determine?
the solute concentration of a solution, determines movement of water across a selectively permeable membrane
If two solutions are isoosmotic, what happens?
movement of H2O at equal rates in both directions
What does osmoregulation control?
It controls solute concentrations and balances gain and loss of water
How are osmoconformers compared to their surroundings?
they’re isoosmotic w/ their surroundings and do not regulate their osmolarity
How are osmoregulators compared to their surroundings?
they expend energy to control uptake and loss in a hyperosmotic or hypoosmotic env
What are stenohaline animals?
Most animals are stenohaline; they cannot tolerate substantial changes in external osmolarity
What are euryhaline animals?
they are animals that can survive large fluctuations in external osmolarity
What kind of animals are osmoconformers?
Most marine invertebrates
What kind of animals are osmoregulators?
Many marine vertebrates and some invertebrates
True or false: Marine bony fish are hypoosmotic to seawater
TRUE
How do animals get rid of nitrogenous metabolites and other waste products?
Excretion
What is the driving force for movement of solutes and water across the plasma membrane?
a concentration gradient of one or more solutes across the PM
Are marine fish hyper or hypoosmotic to their env?
They are hypoosmotic, so they lose water by osmosis and gain salts by diffusion. To balance this they drink sea water and excrete salts
Are freshwater fish hyper or hypoosmotic to their env?
They are hyperosmotic, so they lose salts by diffusion and maintain water balance by drinking very little water and excreting large amounts of dilute urine
What is an adaptation that allows some animals temporarily live in water?
Some aquatic invertebrates in temporary ponds lose most of their body water and survive in a dormant state. This adaptation = Anhydrobiosis
What is an adaptation of most terrestrial animals that helps prevent dehydration?
Body coverings
What are transport epithelia? AND how are they typically arranged?
epithelial cells that specialize in moving solutes in specific directions and they’re typically arranged in complex tubular networks
What is an example of transport epithelia in animals?
An example is in glands of marine birds, which remove excess sodium chloride from the blood
What are the 3 different forms of nitrogenous wastes that are excreted?
1) Ammonia
2) Urea
3) Uric Acid
Which of the 3 forms of nitrogenous bases is the least toxic?
Uric acid
Which organ removes Urea from the blood?
kidney
Which 3 groups of animals mainly excrete uric acid?
1) insects
2) land snails
3) many reptiles including birds
What do excretory systems regulate?
They regulate solute movement b/w internal fluids and external env
What are the 4 key functions of most excretory systems?
1) Filtration
2) Reabsorption
3) Secretion
4) Excretion
What is a protonephridium (Planaria)?
Excretory system that’s made of a network of dead-end tubules connected to external openings
What is metanephridia (earthworm)?
Excretory system (& osmoregulation) that consists of tubules that collect coelomic fluid and produce dilute urine for excretion
What are Malpighian Tubules?
Excretory system in insects that removes nitrogenous waste from hemolymph and functions in osmoregulation
What is the excretory organ in vertebrates that functions in both excretion and osmoregulation?
Kidneys
What is the order of nephron organization?
1) Proximal tubule
2) Descending limb of the loop of Henle
3) Ascending limb of the loop of Henle
4) Distal Tubule
5) Collecting duct
What occurs in the proximal tubule in the nephron of the kidneys?
Reabsorption of ions, water, and nutrients
What occurs in the descending limb of the loop of Henle in the nephron of the kidneys?
Reabsorption of water continues through channels formed by
aquaporin proteins; filtrate becomes increasingly concentrated.
What is movement driven in the descending limb of the loop of Henle?
Movement is driven by the high osmolarity of the interstitial fluid, which is hyperosmotic to the filtrate
What occurs in the ascending limb of the loop of Henle in the nephron of the kidneys?
salt but not water is able to diffuse from the tubule into the interstitial fluid; filtrate becomes increasingly dilute
What occurs in the distal tubule in the nephron of the kidneys?
The distal tubule regulates the K+ and NaCl concentrations of body fluids; the controlled movement of ions contributes to pH regulation
What occurs in the collecting duct in the nephron of the kidneys?
The collecting duct carries filtrate through the medulla to the renal pelvis; one of the most important tasks is reabsorption of solutes and water
Is urine hypo or hyperosmotic to the body fluids?
Hyperosmotic
Which part of the nephron helps regulate pH?
The distal tubule
What is a key terrestrial adaptation of mammalian kidneys?
The mammalian kidney’s ability to conserve water is a key terrestrial adaptation
When is Antidiuretic hormone released?
it’s released into the blood when osmolarity of blood rises above a set point
What is the ADH response pathway in the collecting duct?
Binding of ADH to receptor leads to temporary increase in # of aquaporin proteins in the membrane of collecting duct cells
What are animal hormones?
chemical signals secreted into the circulatory system, and communicate regulatory messages within the body
True or false: hormones reach all parts of the body, but only target cells that have receptors for that hormone?
TRUE
What are the 2 systems that coordinate communication throughout the body?
1) endocrine system
2) nervous system
The endocrine induces many responses, what are 5 of them?
1) reproduction
2) development
3) energy metabolism
4) growth
5) behaviour
Nervous system conveys high-speed electrical signals along neurons. these signals regulate other cells including what?
1) neurons
2) muscle cells
3) endocrine cells
What are local regulators? AND what types of signaling do they act in?
they are molecules that act over short distances, reaching target cells solely by diffusion. They act in paracrine and autocrine signaling
What is an example of a local regulator and what 3 functions does it do?
Prostaglandins function in…
1) reproduction
2) immune system
3) blood-clotting
What 3 things do paracrine and autocrine signaling play roles in?
1) Pressure regulation
2) Nervous system function
3) Reproduction
Are pheromones’ hormones?
NO
What are the 4 functions of pheromones?
1) marking trails leading to food
2) defining territory
3) warning of predators
4) attracting potential mates
What are the 3 major classes of hormones in vertebrates?
1) Polypeptides (proteins and peptides)
2) Amines derived from amino acids
3) Steroid hormones
Which class(s) is/are lipid soluble and can pass easily through cell membranes?
Steroids are the only class that are lipid-soluble, polypeptides and amines are water-soluble
What class of hormone does insulin fall into?
Polypeptide
Prostaglandins fall into what class of hormone? AND what do they promote?
related to fatty acids and steroids and they promote fever and inflammation
What are steroids derived from?
cholesterol
What is usually a response to a lipid-soluble hormone?
Change in gene expression
What hormone regulates metabolism and in frogs it controls metamorphosis?
Thyroid hormone
What is the combination of 3 hormones that controls molting and development in insects?
1) PTTH
2) Juvenile hormone
3) Ecdysone
What is 1 function of the pineal gland?
located in the brain, it secretes melatonin and this release is controlled by a group of neurons in the hypothalamus called the SCN
What is 1 function of the hypothalamus?
It plays a central role in integrating the endocrine and nervous systems. It receives info from nervous system & initiates responses through endocrine signaling
What are 2 hormones released by the posterior pituitary?
1) Oxytocin: regulates milk secretion by mammary glands
2) ADH: regulates physiology + behaviour
How is hormone production in the anterior pituitary controlled?
it’s controlled by releasing and inhibiting hormones secreted from the hypothalamus
What 2 hormones are released by the anterior pituitary and what does it play a role in?
1) Prolactin: has a role in milk production
2) Growth hormone (GH): promotes growth directly + has diverse metabolic effects
What happens if thyroid hormone drops too low?
Hypothalamus secretes thyrotropin-releasing hormone (TRH) causing the anterior pituitary to secrete thyroid stimulating hormone (TSH) which stimulates release of thyroid hormone
What kind of feedback do hormone cascades typically involve?
Negative feedback
What is a hormone released by the thyroid?
Calcitonin: decreases the level of blood Ca2+
What is a hormone released by the parathyroid gland?
Parathyroid hormone (PTH): increases the level of blood Ca2+
What 2 hormones are released by the pancreas?
1) Insulin: blood glucose decrease
2) Glucagon: blood glucose increase
What does the adrenal gland play a role in?
Regulates responses to stress
What 3 glands produce most of the sex hormones?
Gonads, testes and ovaries
What are the 3 sex hormones released by the gonads, testes, and ovaries?
Androgens, estrogens, and progestins
What do the testes synthesize?
The testes primarily synthesize androgens, mainly testosterone. Testosterone causes an increase in muscle and bone mass
How fast can the star-nosed mole catch insect prey in near total darkness?
120 milliseconds
How many appendages on the star-nosed moles nose is used to located and capture prey?
11 pairs of appendages
What is a simple response pathway of a foraging star-nosed mole?
1) Sensory input
2) Integration
3) Motor output
What are the 4 basic functions in sensory pathways?
1) Sensory reception
2) Transduction
3) Transmission
4) Integration
During transmission, if the receptor is a neuron what happens, and id the receptor is not a neuron what happens?
Neuron: More frequent action potentials
Not a neuron: more neurotransmitters released
What are perceptions?
They are the brain’s construction of stimuli
How does the brain distinguish stimuli from different receptors?
based on the area in the brain where the action potentials arrive
What is amplification in terms of sensory pathways?
Strengthening of a sensory signal during transduction
What is sensory adaptation in terms of sensory pathways?
it’s a decrease in responsiveness to continue stimulation
What are the 5 categories of sensory receptors?
1) Mechanoreceptors
2) Chemoreceptors
3) Electromagnetic receptors
4) Thermoreceptors
5) Pain receptors
What do mechanoreceptors do?
Response to pressure, touch, stretch, motion, and sound relies on
mechanoreceptors
What is the knee-jerk response triggered by?
the vertebrate stretch receptor, a mechanoreceptor that detects muscle movement
What does the mammalian sense of touch rely on?
relies on mechanoreceptors that are dendrites of sensory neurons
What do chemoreceptors do?
transmit info about total solute concentration of a solution, and they are in antennae of the male silkworm moth, and are used to detect sex pheromones
What do electromagnetic receptors do?
they detect electromagnetic energy such as light, electricity and magnetism. Used in many migratory animals to orient themselves using the Earth’s magnetic field
What do thermoreceptors do?
respond to heat or cold, and help regulate body temp. Plus some snakes use them to detect infrared radiation emitted by warm prey
Wat do pain receptors do?
detect stimuli that reflect harmful conditions such as excess heat, pressure, or chemicals
What kind of receptors are responsible for hearing and body eqm?
Mechanoreceptors
What organs are mechanoreceptors located in which are used to maintain eqm? (invertebrates)
Statocysts: they contain mechanoreceptors that detect movement of granules called statoliths
What organ in the ear contains mechanoreceptors?
Corti
How do we hear certain frequencies?
Pressure waves in the canal cause the basilar membrane to vibrate, bending its hair cells. Each region of the basilar membrane is tuned to a particular vibration frequency
What are 2 organs in the inner ear used to detect body movement, position, and balance?
1) Utricle
2) Saccule
Both contain granules called otoliths used to perceive position relative to gravity or linear movement
What 3 things can detect angular movement in any direction?
3 semicircular canals contain fluid and can detect angular movement in any direction
What system do most fish and aquatic amphibian have that contains mechanoreceptors?
the lateral line system contains mechanoreceptors that detect and respond to H2O movement
How do monarchs know which way to fly?
Monarch butterflies use the sun as a compass
In humans, perception is based on 3 types of comes, each with a different visual pigment. What are these 3 pigments and what are they called?
1) Red
2) Green
3) Blue
they’re called photopsins
How does focusing occur in the eye?
focusing occurs by changing the shape of the lens
What are olfactory receptor cells?
neurons that line the upper portion of the nasal cavity
