Organisation and the Vascular Structures
Organisational Complexity of Flowering Plants
Root System
Function:
- Anchor
- Absorb water and minerals from the soil
- Store food
Types of Roots:
- Tap Root; Triangular primary root with lateral/secondary roots emerging from it. Many root hairs grow from tap roots. E.g. carrots
- Fibrous Roots: Mass of equally sized branch roots. E.g. Grass
- Adventitious Roots: Roots that appear at other parts of the plant, such as the aerial parts of plant. E.g. Ivy
Longitudinal Section of a Root
- Zone of Protection: Root cap protects the root tips as it grows through the soil
- Meristematic Zone: Zone of cell division, forms into 3 types of plant tissue; dermal, vascular and ground
- Zone of Elongation: Cells get longer as result of plant growth regulators
- Zone of Differentiation: Cells begin to change and form into select tissues e.g. phloem.
Transverse Section of Root
Root Hairs: Adapted for maximum absorption of water and minerals for example they provide an increased surface area of the root.
Shoot System
* Stem, Leaves, Flowers and Seeds
Function:
- Support
- Transport
- Store food
Leaves
- Photosynthesis
- Transpiration
- Gas exchange
- Store food
In leaves veins are in two variations
- Parellel, most monocots have parellel leaves such as grass
- Net, Dicots tend to have net veniation
Internal Structure of a Leaf
- Palisade layer contain the highest density of chloroplasts as they receive the most sunlight
- Stomata open and close which is controlled by the guard cells
- Leaves contain many air spaces which gives greater surface area for gas exchange.
Stem
Function: Mainly in transport and support.
- Have lenticels for gas exchange
- Also functions in growth
- Nodes are areas where branching occurs and internodes are the spaces in between.
Longitudinal Section of a Stem Transverse Section of a Monocot Stem
Transverse Section of a Dicot Stem
Classification of Flowering Plants
Monocots:
- Seeds have one cotyledon (seed leaf)
- Mainly herbacious (no woody parts)
- Parallel veins in the leaf
- Long narrow leaves
- Vascular bundles are scattered at random in the stem
- Flowering parts in multiples of 3
Dicots:
- 2 cotyledons
- Herbacious/woody
- Veins form a branching network
- Broad leaves
- Vascular bundles form a ring in the stem
- Flowering parts in multiples of 4/5
Xylem:Transports water and minerals up the plant
- Cells are dead and have no nucleus or cytoplasm
- Has lignin for strength
- 2 Types; tracheids and vessels
- Transports water and minerals upwards
Phloem:
- Living cell - Transports food in the form of sucrose upwards and downwards- No nucleus but large one in the companion cell
Prepare and examine microscopically the transverse section of a dicotyledonous stem
1) Cut out the stem at the internode
2) Cut out a wedge shape from a carrot
3) Place stem in wedge cut out and cut thin slice of stem with a backed blade, place onto slide and add a drop of water to prevent the sample from drying out
4) Lower glass coverslip from a 45 degree angle
5) Observe sample at lower magnification first and then increase the magnification.
Organisational Complexity of the Human
The Human Circulatory System
Closed Circulation System: Blood never leaves the blood vessels
- Oxygen delivered without blood leaving the vessels
- Faster delivery of oxygen
- Enables the body to control what areas of the body receive blood
Open Circulation System: Blood flows out of the vessels and surrounds cell tissue, blood flows back to heart through pores called ostia. E.g. insects, spiders, worms
Artery
- Thick walls
- Small lumen
- No valves
- Oxyginated (except pulmonary artery)Walls: thick, tough, elastic
- Outer layer = Collagen
- Inner layer = Elastic tissue and muscle
- The muscle is a smooth muscle and contracts to push blood along
- Endothelium cells are the inner most layer of arteries and veins
- Carry blood to the smaller arterioles
Vein
- Thin wall
- Large lumen
- Valves
- Deoxyginated blood (except pulmonary vein)
Layer of smooth muscle to push blood along, receive blood from the smaller venules
Systematic Circuit:
- Body
Pulmonary Circuit:
- Lungs
* Double Circulatory System
Coronary Artery:
- Heart
Portal System:
- Starts and ends in capillaries, e.g. Hepatic Portal System; small intestine to liver
Blood Transport System
Functions:
1) Transports glucose, oxygen, hormones, waste products
2) Defense against diseases and infections
3) Temperature regulation
- 5-6 litres of blood in the body
Blood Components
Plasma: Liquid medium in which other blood components are suspended in
Red Blood Cells: Transports oxygen, contains haemoglobin
- No nucleus
- No mitochondria
- Biconcave shape
- Presence of haemoglobin
White Blood Cells: Prevents infections and disease
- Lymphocytes: Recognise individual pathogens and produce antibodies against them
- Monocytes: Recognising foreign pathogens and digest them in a process called phagocytosis
Platelets: Prevents pathogen entry, creates blood clots
Blood Groupings
- A, B, AB, O; depends on the types of proteins present on the surface of the red blood cells.
- Rhesus factors; Person can either have or not have the rhesus factor, either rhesus postive (have) or rhesus negative (don't have)
The Heart
Cardiac Cycle:Systole/Systolic = High pressure
Diastole/diastolic = Low pressure
Pacemaker:
- There are two in the human
- Made up of nervous tissue and fibre
1) SA Node; Main pacemaker
- SinoAtrial Node
- Located in the top right atrium
2) AV Node:
- AtrioVentrical Node
- Located between the right atrium and the right ventricle
* Atrial Systole = Atrium contract
* Ventricular Diastole = Ventricle relax
Cycle
1) Blood from vena cava or pulmonary artery enters the atrium
2) Atrium contracts and blood enters the ventricle
3) Ventricles contract/systole, flaps of tri/bicuspid valves close to prevent the backflow of blood
4) Blood pumped into major arteries
5) All valves e.g. semilunar valves close and more blood enters the atium
6) Cycle begins again
* Pacemakers receive an electrical signal which stimulates the contraction of the muscles
Dissect, display and identify a sheep's heart
1) Wash heart to remove any blood clots
2) Place on disection board
3) Distinguish right side from left, left is tougher as it has more muscle
4) Distinguish front from back, back is flat and front is rounded
5) Identify coronary artery on front surface of the heart
6) Flap like tissue at the top of the heart = auricles
7) Large hole next to right auricle is the superior vena cave down from this is the inferior vena cava
8) Next to the left auricle is the pulmonary vein
9) In the centre at the top of the heart is the aorta
10) Pulmonary artery is just behind and to the left of the aorta
11) Turn heart so its lying on its front surface. Cut with a scalpel into the superior vena cava down through the walls of the right atrium and ventricle.
12) Open up the incision and identify the right atrium, right ventricle, papillary muscle, chordae tendonae, tricuspid valve
13) Insert a probe down the pulmonary artery which should appear in the right ventricle.
14) Cut through the pulmonary artery to identify the semilunar valve
15) Using a scissors cut through left atrium and left ventricle
16) open up incision and identify, left atrium, left ventricle, the biscuspid valve. papillary muscle, and chordae tendinae
17) Stick a probe down aorta, will appear in the left ventricle
18) Cut through aorta and identify semilunar valve
Investigate the effect of exercise on the breathing rate or pulse of a human
- Measure pulse, go for run, measure pulse
- Pulse rate increases! Quelle surprise
Pulse: Alternate contraction and relaxation of artery as blood passes through
Blood Pressure: Force blood exerts on the walls of the blood vessels
- Blood pressure measured by systolic and diastolic pressure
- Atheroclerosis is high blood pressure caused by the build up of fatty tissue in the blood vessels
The Lymphatic System
- Part of the immune system and directly linked to the circulatory system
- Collects excess fluid around the cells and returns it to the blood = interstitial fluid, extracellular fluid. ---> Formed by plasma leaving the capillaries
Structure of the lymphatic system:
Lymph: Clear liquid collected from around cells and transported by the lymphatic system back to the bloodstream.
Lymph nodes: Small spereical shaped organs organs in the lymphatic system which contain many white blood cells
Lymph vessels: Narrow dead ending tubes which collect lymph and are present in every tissue and organ in the body
Spleen: Organ located to the left of the stomach. Produces lymphocytes and filters out bacteria, viruses and abnormal cells
Tonsils and Adenoids: Produce lymphocytes during an infection
Thymus: Located above the heart and functions in maturing lymphocytes
Functions:
- Filters lymph through lymph nodes
- Absorbs fats from the small intestine, into lacteals. Lacteals absorb lipids after digestion
- Responsible for the maturation of certain white blood cells
- Helps fight infections
- Forms the inner ear fluid needed for hearing and balance
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