Understanding Mitosis, Meiosis, and Genetic Variation
Main Stages of Mitosis
Prophase: cell structures break down and chromosomes divide
Metaphase: chromosomes line up at the middle of the cell
Anaphase: sister chromatids separate and move to opposite ends
Telophase: cell division nears completion and normal structures are re-established
Mitosis vs. Meiosis I
Meiosis has two rounds of genetic separation and cellular division, leading to non-identical daughter cells, unlike mitosis.
Meiosis and Genetic Variation
Prophase I allows for genetic diversity through
Read MoreNutrition: An Exchange of Substances and the Digestive System
Nutrition: an exchange of substances
In order to carry out the nutrition function, living organisms need an exchange of substances to take place between their surrounding environment and their cells. This exchange occurs in different ways according to whether the organism is unicellular or multicellular.
1.1. How substances are exchanged
The nutrition function is performed through the joint action of different systems. The systems involved in human nutrition are:
1. The digestive system: This system
Read MoreNeurotransmitters and Their Role in Brain Function
Excitatory or inhibitory, synthesis, storage, inactivation, receptors, sources, role, toxins
ACh: E, choline+acetyl coenzyme A (CAT), trans to vesicles by ST, acetylcholinesterase (breakdown in synaptic cleft), nicotinic (iono) and muscarinic (meta), nucleus basalis/septal nuclei, neuro-muscular junction, memory, attention, cholinergic degeneration. 1st stage of Alzheimer’s, organophosphates (pesticides and Sarin) inhibit acetylcholinesterase
Glutamate: E, glutamine, trans. to ves, by st, EAAT into
Read MoreUnderstanding the Heart, Digestive System, and Enzymes in the Human Body
The heart
Blood goes from heart to lungs via pulmonary artery to get O2, then O2 blood goes back to heart via pulmonary vein. Heart pumps O2 blood to the body via the aorta, it goes round the body and the d/o blood is pumped back to the heart via the vena cava to be pumped to the lungs for O2 again.
Problems with the heart
Inverted valves, causing blood to flow the other way, treated by fitting a replacement valve, artificial or biological, invasive surgery and risk of rejection. If the heart stops
Read MoreRespiratory and Urinary Systems: Functions and Common Problems
The Respiratory System
The entry point for air into the body is primarily through the nose, with some air entering through the mouth. The nose serves to warm, clean, and moisten the air. The nose consists of two nostrils (nares), a septum, and tube-shaped cartilage inside the nose (turbinates). The nose is very vascular, which means that it contains many blood vessels, which is why the nose bleeds easily. The blood in these vessels warms the air as it enters the rest of the respiratory tract. In
Read MoreFemale Reproductive System: Ovarian Structure and Function
SIST. FEMALE REPRODUCTIVE: Ovarian
- Stroma: the outside of the ovary (bark)
- Spinal: inner
- Follicles: structure, rounded with follicular fluid contain Colloids (within the stroma)
- Are released over 450 eggs during the reproductive stage
- Hypothalamo-GnRH (inhibitor of gonads) – Pituitary-FSH-LH-follicle development – ovulation
FOLLICLES
- F. Primordial: (1 layer cel.foliculares without liquid foli)
- F. Primary: (1 layer cel.c / liquid)
- F. Primatio multilayer (3 layers of cell.)
- F.de Graff (release the egg)