B2.3 Flashcards
What are the top two chambers and bottom two chambers in the heart
Top two are atriums, right and left, and bottom two are right and left ventricles
What is septum
Muscle in centre of heart that separates left and right sides in heart
What happens in right side of heart
Blood enters vena cava into right atrium and through the valves into right ventricle. Up through pulmonary artery and into the lungs.
What halve separates the atrium and ventricles
atrio ventricular
What’s special about the pulmonary artery
Only archery carrying de oxygenated blood, from the right ventricle to the lings
What valve is between the ven cava and heart and the aorta and the heart
Semi lunar valves
What happens in left side of heart
Blood enters left atrium through the pulmonary vein with oxygenated blood. Blood goes through strip ventricular valve into the left ventricle. Blood pumped through semi lunar valve through aorta and into the rest of the body
What kind of muscle is the heart made of
Cardiac muscles
What are the superior and inferior vena cavas
Superior, blood from above the heart eneters heart through here, blood from below heart enter it through inferior vena cava
What are fossils
Preserved traces or remains of organisms that lived th us ands or millions of years ago
What is the fossil record
The history of life on earth shown through changes in fossils
Why are there gaps in the fossil record
Soft tissue organisms don’t have many fossils as most of their body decays when they die and many other organisms have the hard part of their bodies destroyed before they can be fossilised. There may also be other fossils we have yet to find
What is the pentadactyle limb structure
Arm Kim's consisting from top to bottom Humerus Radius and ulna bones Carpals Phalanges
What does the pentadactyl limb show us
All vertebrates evolved from one common ancestor and changed to adapt to their environment
How do plants grow
The area beneath the tip of a shoot or root has cells called meristem. These cells are always dividing and elongating, this causes growth.
What is special about meristem
The older meristem cells can differentiate like stem cells into other cells such as a leaf one with chlorophyll or a root hair cell
Why can’t animals re grow limbs but plants can regrow leafs
Plants always have meristem than can differentiate into any cell, adults have a few stem cells and they can’t differentiate into all the different cells needed to regrow body parts
Why is blood an organ
It is made up of lots of different cells that work together to carry out a function
What is plasma
Yellow substances accounting for approx 55% of blood, it carries food substances, hormones and carbon dioxide
What are red blood cells
Specialised cells in the blood accounting for approx 45% of blood and carry no oxygen, they have no nucleus to allow more room for the oxygen
How do red blood cells carry oxygen
They contain haemoglobin that reacts with the oxygen in the air to form oxyhaemoglobin and then reverses the reaction at other cells to pass on the oxygen
Why are red blood cells biconcave disc shaped
This this them a large surface area to volume area so lots of difffusion
What are platelets
Fragments of other cells and they clot the blood when exposed to the air
What are white blood cells and what do they do
Cells used for the bodies defence. Some produce antibodies that when release, surround the foreign cell and destroy it, others surround the foreign cells themselves to destroy it
What is tissue
The thing formed when a group of the same type of specialised cells form a tissue
What is an organ
Something containing several different types of tissue that work together for a particular function
How does blood travel through the body
Blood enters heart from either superior or inferior vena cava. From here it goes through the semi lunar valves and into the right atrium. When it’s full it goes through atrio ventricular valves and into the right ventricle. When this is full, it pumps it into the the pulmonary artery. Here it goes into the lungs and becomes oxygenated. Then it enters the pulmonary vein and into the left atrium through semi lunar valves. Then once it’s full, goes through atrio ventricular valves and into the left ventricle. When this is full, it pumps it into the aorta which takes it around the body. Then it goes from arteries through capillaries and into veins. Then they go back to vena Ca as
What is the circulatory system
The system made of arteries, veins, capillaries and the heart
Properties of capillaries
Single cell thick walls for easy diffusion
Properties of arteries
Thick muscular walls to deal with the pressure and thin space in the middle
Properties of veins
Thin muscle walls as lower pressure, large space inside so less friction so blood flows easier
What are the parts of the alimentary canal
Mouth Oesophagus Stomachs all intestine Pancreas Large intestine Anus Liver Gall bladder
What happens at the mouth
Food is chewed into small pieces to increase surface area for enzymes. Amylase in Sylvia stars breaking down carbs into sugars. Spit helps lubribcate food and tounge rolls it into a bolus before it is swallowed
What happens in oesophagus
Peristalsis pushes the bolus into the stomach
What happens into the stomach
Peristalsis churns it up into a paste and the acid helps break it down. Pepsin breaks down proteins into amino acids
What happens in small intestine
Large insoluble molecules are broken into small soluble ones. Lots of enzymes from pancreas help break down food into digestible sizes. Molecules of processed food diffuse into the blood through the villi.
What happens in the pancreas
The organ makes the digestive enzymes and releases them to where they need to go
What happens in large intestine
Undigested food passes through here. Water diffuses into the blood and all that remains is the poo
What happens at anus
End of the alimentary canal where poo exits the body
What happens at the liver
Blood with digested food passes through here to be processed. Some molecules are broken down even more, some built up into larger molecules. Bile is also made which helps break down fats.
What happens at gall bladder
Stores the bile made by the liver and releases it when nesicary
How are carbs digested
Carbohydrases break down carbs, starches into simple sugars. Amylase breaks carbs into simple sugars and other carbohydrases break the simple sugars into glucose
How are proteins digested
Proteins are broken into amino acids which the body uses to make its own proteins. Pepsin is a protease made in the stomach and works at the acidic conditions, 2-3pH. However in the small intestine, trypsin breaks down proteins as it’s more alkali, ph8.
How are fats broken down
Bile emulsifiers fatty globules into smaller ones to give them a larger surface area, lipases then break them down into fatty acids and glycerol
What does bile do
Emulsifies the fatty globules, makes poo brown and makes small intestines alkali, rather than acidic
Why are villi so important
They dramatically increase the surface area of the small intestine which means that a lot more diffusion can take place than if it was a smooth surface s
What are villi and what do they do
Each villus is one cell thick and has a good network of capillaries making them ideal for diffusion. They re single cell thick for easy diffusion and the good network of capillaries means once a substance diffuses into it, the blood takes it away quickly so the concentration gradient between the villi and food means the food is always diffusing into the villi
What does coelliac disease do
Villi are lost or covered up so the surface area of the small intestine is reduced so less diffusion, this makes victims of the disease very skinny and weak
What are probiotics
Foods containing friendly bacteria such as lactobacillus and bifidobacteria, these supposibly make you healthier
What are plant stanol esters and what do they do
They are oily substances found in plants which stop the small intestines absorbing cholesterol which helps reduce heart problems and heart failure
What are prebiotics
They can’t be absorbed by us but are beneficial for probiotics, acting like food. Ingesting these increase number of probiotics in the body
