Animal Classification: Annelids, Insects, Cephalopods, and More
Animal Classification
Annelids. The segmented worms have bodies divided into repeated segments, aiding movement. They possess a true coelom filled with liquid, located between the body wall and digestive tract. They have a closed circulatory system for distributing gases and nutrients. They have excretory organs called nephridia, functioning like kidneys. They reproduce both asexually and sexually.
Insects are the only flying invertebrates. They have a pair of antennae, three pairs of legs, and
Read MoreDigestive System Disorders: Celiac Disease, Lactose Intolerance & More
Digestive System Disorders
Celiac Disease
Celiac disease is a permanent intolerance to gluten, a protein existing in wheat, barley, rye, and oats. It occurs in people genetically predisposed to gluten.
Lactose Intolerance
Lactose intolerance is an intolerance to milk sugar produced by a deficiency causing lactose. Lactose cannot be absorbed and therefore passes intact to the colon, presenting as diarrhea.
Regulation of Stomach Emptying
There are two mechanisms:
- Hormonal: Enterogastrin is released into
Human Body Systems: Nerves, Hormones, Senses & Functions
The nervous system (SN) perceives sensations and responds to stimuli to maintain our body’s internal balance (homeostasis). It consists of central and peripheral components and various types of cell-secreted chemicals. Neurons have dendrites (short, numerous, capture signals) and an axon (single, long, transmits signals).
Pituitary gland (Hiòfisi) produces hormones including: antidiuretic hormone, prolactin, follicle-stimulating hormone, luteinizing hormone, and oxytocin.
The thyroid gland produces
Read MorePlant and Animal Reproduction: Types and Processes
Reproduction in Living Organisms
Reproduction is a vital function that enables the continuation of living descendants.
Types of Reproduction
There are two main types of reproduction:
- Asexual Reproduction: A simple process where one organism creates an identical copy of itself.
- Sexual Reproduction: A complex process involving two parents that produce special cells (sex cells or gametes). Male gametes are called sperm, and female gametes are called eggs. When these gametes unite, they create a new organism
Cell Cycle Phases and Cellular Division: Mitosis vs. Meiosis
The Cell Cycle
Interphase: This is the initial, long stage where cell division does not occur. It is characterized by cell growth and the development of normal metabolic activities.
- G1 Phase: Follows the previous cell’s mitotic cycle and is a stage of cell development. At the end of the G1 phase, there is a point of no return (the restriction point or R point), after which the entire process cannot be stopped. Phases S, G2, and M will inevitably follow. Some cells, before reaching the R point, undergo
Cell Structure and Function: Prokaryotic and Eukaryotic Cells
Cell Structure and Function
The cell is the structural unit of living beings. The cell is the functional unit of living beings; it carries out all the metabolic processes that allow it to live. Every cell comes from another pre-existing cell. The cell is the genetic unit of all living beings.
Levels of Organization
The subject has different organization levels, each more complex structurally and functionally than the previous one: subatomic particles, atoms, molecules, macromolecules and supramolecular
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