Animals Flashcards
Name the 3 types of skeletons
Hydrostatic
Exoskeleton
Endoskeleton
How does the skeleton produce movement?
Resists the pull from skeletal muscles
Describe hydrostatic skeletons
Muscles surrounding a fluid filled cabity exert pressure to produce movement
Describe hydrostatic skeleton in an earthworm
Fliud filled cavity. Circular muscle. Longitudinal muscle.
What is a circular muscle?
Forms a circle all the way round. Contract = narrower and longer
What is a longitudinal muscle?
Length ways - flatter and shorter
Describe an exoskeleton.
External to organs and soft tissue
What are Mollusc shells made of?
Composite material: calcium carbonate and protein
How does protein affect an exoskeleton?
More flexible - less likely to snap
Describe an Arthropod exoskeleton. (A cuticle)
Contains chitin embedded in a protein matrix. Arthropods have joints so needs to be flexible.
Chitin = long fibrils.
Cross linking between proteins.
Hardened by calcium carbonate
Describe an endoskeleton?
Skeleton inside thebody. Vertebrates.
What can the skeleton be divided into?
Axial and appendicular
What are the axial regions of the skeleton?
Spine, ribcage, skull
What are the appendicular regions of the skeleton?
Bones appended on the acial
What does bone contain?
Collagen (1/3). Calcium phosphate crystals (strengthens).
What would happen if bone had no minerals?
It would bend
What would happen if bone had no collagen?
Would be too brittle - likely to snap
What is brittle bone disease?
Mutation - less collagen
What are osteoblasts?
bone producing cells, secrete enzymes, collagen production
What are osteocytes?
mature bone cells, encased in the bone
What are osteoclasts?
break down the bone
What is osteoperosis?
bone weakness → increased breaking down of bone compared to making bone
How are skeletons able to move?
Joints
What are the different types of joints?
Hinge Ball and socket Plane Pivot Condylar Saddle
How is the type of joint formed determined?
By the shape of the end of thebone
What is torque?
Rotational movement of an object arpimd am axid
What is the equation for torque?
t = F x r
Which type of levers have more range of moevement?
Long levers
What are the main functions of the skeleton?
Movement. Protection. Support
What are the 3 types of muscle?
Heart. Smooth. Skeletal
What is the smallest unit of muscle?
Muscle fiber - muscle cells
How are muscle fibers formed?
Fusion of lots of cells - they are multinucleated
What is the name of a bundle of fibers?
Fascicle
What is the epimysium?
connective tissue - outside, surrounds all the muscle, continuous
What is perimysium?
connective tissue - surrounds fascicles
What is endomysium?
connective tissue - surrounds individual muscle fibres
Describe myofibirl
2 overlapping myofilaments Thick = myosin Thin = actin Secured by the Z disc Known as the sarcomere
Describe muscle contraction.
Increased overlap Contraction → sarcomere shortening Shortening of muscle Size of filaments doesn’t change They overlap by binding
Describe thin filaments
Actin
Contains binding sites for myosin
Binding sites covered by tropomyosin
When calcium is present → tropomyosin moves off
Describe thick filaments
Myosin
Binding site for actin and one for ATP
Contain a tail and a head
Myosin heads protrude out ready to bind
Describe binding in the sliding filament theory
Bond = cross bridge
ATP binds to myosin head
Dissociation of myosin and actin
ATP broken down → ADP and Pi
Myosin head pulled back to ‘cocked’ position
Myosin can now bind to actin as ATP is no longer present
ADP + Pi released → myosin head moves back (power stroke) → thin filament slides across the thick filament
Describe contraction coupling (excitation)
Motor neuron connects to muscle fibre through the neuromuscular junction
T-tubules close to sarcoplasmic reticulum → calcium store
Action potential propagates along sarcolemma to T tubules
Sensed by sarcoplasmic reticulum → releases calcium
How do T tubules work?
high density of calcium channels (DHPR) Opens Influx of calcium ions into muscle cell Channel from sarcoplasmic reticulum Massive of influx into muscle cell
What is the equation for aerobic respiration?
O2 + glucose → CO2 + H2O + ATP
What is the respiratory membrane?
where gas exchange takes place
How do the simplest invertebrates get nutrients?
gas exchange occurs across the entire surface of the organism and diffusion of the gases is sufficient
What is ventilation?
movement of respiratory medium to respiratory surface eg breathing
What is diffusion?
movement of gases across respiratory membrane
What is circulation?
system to carry gases around the body → usually movement of fluid
What are 3 respiratory surfaces?
gills, tracheae, lungs
Describe the gills
Outfoldings of respiratory membrane Highly complex as there’s low oxygen concentrations in water Really thin Huge surface area Moist
What are gills like in a salamander?
external gills
What are gills like in a bony fish?
internal gills
Describe breathing in a bony fish
2 sets of gills either side
Ventilation → through the mouth and over the gills
Achieve by swimming continuously
Operculum → flap covering gills → can expand drawing in water
Gill arches contain gill filaments → discs lamellae
Countercurrent → blood in opposite direction to waterflow
What is the oxygen uptake like in terrestrial animals?
Oxygen uptake = higher
How do insects breathe?
Through a tracheal system
Describe the open circulatory system in insects
Open circulatory system not involved in transporting gases
All cells bathed in respiratory medium
Doesn’t need to be transported
Can just use diffusion
How do insects ventilate?
rhythmic body movements
What is the process of breathing in insects?
Spiracles (air enters) → large tube called tracheae (strengthened by chitin) → air flows through smaller tubes (tracheoles)
What does having lungs mean?
Restricted to one location and so requires circulatory system to transport gases to cells
Where does the air move through in a human?
in through nose and mouth to pharynx → trachea → bronchi → lungs → branch into small bronchi → and bronchioles → alveoli
Where does gas exchange occur in the lungs?
Alveoli
What are the alveoli surrounded by?
A dense bunch of capillaries
What are features of alveoli?
Thin. Form a large surface area.
Describe ventilation in a human.
Inhalation and exhalation
Diaphragm contracts
Moves down
Lungs expand
Draws the air in → pressure gradient → negative pressure
Pressure drops and volume increase (inversely proportional)
Exhalation → passive → diaphragm relaxes
How can frogs respire?
Through the skin (in water) or via the lungs
Describe the process of respiration in a frog
Mouth floor lowers, air flows in
Reduces pressure → volume increases
Mouth floor contracts forcing air into the lungs
How do birds ventilate?
Using air sacs
What air is in the anterior air sac?
Stale air
What air is in the posterior air sac?
Fresh air
Describe respiration and ventilation in a bird.
Lungs (parabronchi) are unidirectional
Inhalation → air sacs fill
Has valves
Exhalation → air sacs empty, lungs fill
Need 2 rounds for air to be completely circulated
Need to be efficient → high energy for flight → huge oxygen requirement
Crosscurrent flow → blood flows at an angle to the air flow
Describe haemoglobin.
4 subunits → globular protein
2 Alpha subunits
2 Beta subunits
Heme group → oxygen binding site → iron group Fe2+
How is oxygen carried in the blood if its not soluble in blood?
Iron ion binds to the oxygen
Can bind 4 molecules of oxygen
What happenns when a molecule of oxygen binds to haemoglobin?
Binding causes a conformational change in the haemoglobin → makes it easier for future molecules to bind
What is the Bohr effect?
pH affects Lower pH moves to the right Reduces affinity Less oxygen binding Lactic acid in active muscles A drop in pH Affinity for oxygen is reduced More likely to release oxygen
What organisms can use diffusion?
Single celled and simple multicellular organisms
Why do larger organisms need a circularotry system?
Diffusion happens at one spot and then is deilvered y a circulatory system
What is an open circulatory system?
- Fluid is pumped through a large muscular tube
- Fluid propelled through
- Rhythmic contraction of muscles
- Fluid leaves tube and empties into the body cavity
- Vessels are open ended
- Cells are bathed in the fluid
What are some examples of organisms with an open circulatory system?
Invertebrate. Arthropods.
What is the circulatory fluid in organisms with an open circulatory system called?
Hemolymph
What are the problems with an open circulatory system?
- Limited control over where to divert fluid
2. Lower pressure
What is a closed circulatory system?
- Fluid is pumped through closed ended vessels
- Uses a pump eg the heart
- Higher pressure is created
What are cells in a closed circulatory system organism bathed in?
Interstitial fluid (outside of vessels)
What does a vascular network mean for an organism?
There is more control
What do interstitial fluid and blood have in common?
Composition - water and ions
What is blood composed of?
Proteins. Blood cells. (Too big to leave vessels)
Describe the features of interstitial fluid.
- Environment the cells are exposed to
- Involved in homeostasis
- Ionic gradient maintained by Na+/K+ ATPase
What are the 5 main categories of vessels?
- Arteries
- Arterioles
- Capillaries
- Venules
- Veins
Describe the structure and function of the artery
- Wall = thick
- Blood pumped into from the heart
- High pressure
Describe the structure and function of the capillaries.
- Thin walls
- Where gas exchange/diffusion takes place
- 1 cell thick
- Allows gases and nutrients to pass through
Describe the structure and function of the veins
- Lowest pressure
- Don’t need thick walls
- Valves to prevent backflow
- Muscles push against the veins
What are the 3 layers in blood vessels?
Inner layer. Middle layer. External layer.
What is the inner layer in a blood vessel?
Tunica intima. Endothelium.
What is the middle layer in a blood vessel?
Tunica media. Elastic and smooth muscle
What is the external layer in a blood vessel?
Tunica adventitia. Provides support
What happens every time a vessel branches?
Gets smaller in diameter but get many more vessels
What does vessel branching mean for an organism?
Can quickly direct blood eg to skeletal muscle. Cardiac output increases
How are arteries the primary site for blood flow regulation?
- Tissues more active
- More ATP
- More oxygen needed = greater blood supply
- Drop in oxygen
- Detected by smooth muscle
- Aterioles dialte
- Less resistance
- Increased blood flow
What is autoregulation?
Decresses blood pH. Increased K+ prostaglandins, adeonisne
How does adenosine regulate blood flow?
- Increases during exercise
- More blood flow through femoral artery
Describe blood flow in a fish.
- Heart = 2 chambers
- Single system
- Flows through the heart once
- Low pressure
- Not very active –> not possible for land animals
What is meant by double circulation?
Goes through the heart twice. Two different circuits
What is the pulmonary circuit?
heart → lungs → heart
What is the systematic circuit?
heart → body → heart
Describe circulation in amphibians and reptiles.
- 3 chambered heart
- Empty into ventricle
- Higher pressure
- Mixing oxygen rich and oxygen poor blood
How many heart chambers do birds and mammals have?
- 2 atria and 2 ventricles.
Describe the blood flow in a double circulatory system?
Blood → left ventricle → supplies capillary beds → returns to right atrium → right ventricle → pumped to lungs → returns to left atrium
What are the features of the vena cava?
Vena Cava → deoxygenated blood → largest vein
Inferior = lower
Superior = upper
Where does blood flow in the right atrium?
Right atrium → blood flows from right atrium to right ventricle
Where does blood flow from the pulmonary artery?
Takes blood to the lungs
Have right and left branches
Where does blood flow from the right ventricle?
Blood is ejected to the lungs
Through pulmonary artery
What blood does the pulmonary veins carry?
Oxygenated blood
Where does blood from the left atria flow?
flows to left ventricle
Where does blood from the aorta flow?
branches to direct blood
Arteries to head and arms
Abdominal aorta
Where does blood from the left ventricle flow?
Pumps to aorta
Why is the left wall so much thicker than the right in the heart?
Higher pressure
What happens during atrial systole?
Contraction of both atria. Blood flows into the ventricles
What happens during ventricular systole?
Contraction of the ventricles. Isovolumetric contraction
Start to contract but no blood ejected yet
Not enough pressure
Ventricular ejection
Blood leaves and enters the arteries
What happens during ventricular diastole?
Isovolumetric relaxation
Started to relax but no change in volume
Ventricular filling
Passive
Why do we need nutrients?
To produce energy
What is the gastrointrestinal tract?
Involved in digestion - extracellular. Specialised body cavity. Gut
What are the 5 main functions of the gastrointestinal tract?
- Ingestion
- Digestion
- Absorption
- Secretion
- Excretion
What happens at the mouth?
Chew - breakdown
What happens at the salivary gland?
Saliva produced - digestion