3 functioning systems Flashcards
Know the structures and functions of the root & shoot systems of plants
Shoot system: the above-ground system of plants — stem and leaves, reproductive organs, flowers and fruit
- site of photosynthetic organs
- site of reproductive organs
- transport of sugars
Root system: the below-ground system of plants — root, lateral roots and root hairs
- anchors the plant in the soil
- absorption and conduction of water and minerals
- storage of excess sugars (starch)
Know the tissues that make up the vascular tissue and what each transports
Xylem: transports water and minerals throughout a plant and provides a plant with support
Phloem: transports sugars and other organic compounds
Know how water is taken into, transported though, and lost from plants
- Water is absorbed from the soil by roots and passes into xylem tissue, which carries it to all parts of the plant.
- Some of the water is used by cells but much passes through stomatal pores in leaves
- Water is lost by transpiration
Explain the properties of water that allow it to be transported
Cohesion: water molecules tend to stick together
Adhesion: water molecules tend to stick to the walls of a container
These properties prevent the water column from breaking apart and pulling away from xylem vessel walls
Know the difference between cells, tissues, organs and organ systems
Cells: basic unit of life, can carry out all processes of life, such as metabolism and reproduction.
Tissues: group of similar cells that share a common function and structure.
Organs: group of different tissues that work together to perform a specific function
Organ systems: group of organs that work together to perform a specific function in the body
Describe the structure and overall function of the endocrine system
Structure: hypothalamus and glands
Function: secretion of hormones that regulate cells
and organs
Explain how hormones travel through the body to target cells
- Hormones released into bloodstream to reach specific target cells
- Target cells have receptors that recognise and bind w/ specific hormones to trigger a physiological response
- Signalling pathway is activated that leads to cellular response (E.g. activation of an enzyme, changes in gene expression, or changes in membrane permeability
(Hormones are broken down and cleared from the body through metabolism or excretion).
Explain how target cells receive hormonal signals and what changes are caused
- Hormones cause cellular changes by binding to receptors on target cells
- No. of receptors on a target cell can increase or decrease in response to hormone activity
State the structures that make up the mammalian excretory system
Structure:
- kidneys (filtration, tubular reabsorption, tubular secretion & excretion)
- ureter
- urinary bladder
- urethra
Function:
- removes metabolic and other wastes from the blood
- plays a role in water balance
State the different methods of excretion *
Urinary excretion: Kidneys filter waste products and extra fluid from the blood to form urine, which is then eliminated from the body through the urethra.
Sweat excretion: Sweat glands secrete sweat to regulate body temperature and eliminate waste products from the body.
State the different types of nitrogenous waste
- ammonia and urea from the metabolism of protein
- guanine from the breakdown of nucleic acids
- creatine and creatinine from the metabolic activities of skeletal muscle
Explain how a nephron works
Function: filters the blood and produces urine
- Blood enters the glomerulus, capillaries filters blood into the Bowman’s capsule
- Filtrate enters the proximal tubule where important substances are reabsorbed back into the bloodstream
- Filtrate then flows into the loop of Henle where more important substances are reabsorbed depending on the body’s needs
- Filtrate enters the convoluted tubule where final adjustments are made to the urine’s composition
- Urine flows into the collecting duct and is transported to the renal pelvis where it drains into the ureter and bladder for storage and elimination
