Endocrine System: Adrenals, Pancreas, and More
The Endocrine System: A Closer Look
Adrenal Glands
The adrenal glands are two small glands located in the abdomen, on either side of the vertebral column, atop the kidneys. They secrete adrenaline and noradrenaline, which act in stressful situations, promoting alertness and wakefulness. They also secrete corticosteroids:
- Glucocorticoids: Involved in the metabolism of carbohydrates, proteins, and fats, and block inflammatory responses to allergic reactions.
- Androgens (testosterone): Have a masculinizing
Microbiology Concepts: Taxis, Endobiosis, Symbiosis, and Gram Staining
Key Concepts in Microbiology
Taxis
Taxis is the directed movement of a bacterium in response to a concentration gradient, either physical or chemical, allowing it to position itself where it can better perform its vital functions. There are two types:
- Attractants (+): Substances that cause bacteria to move towards them, usually nutrients.
- Repellents (-): Substances that cause bacteria to move away, typically toxic.
Bacteria have receptors on their surface capable of distinguishing between harmful substances
Read MoreChromosomes, DNA, Genetic Engineering, and Biotechnology
Chromosomes
The number of chromosomes in a species remains constant. During the formation of sexual cells, the parents do not merely halve the number and rather carry 2 copies of each chromosome, only one is passed on.
Karyotype
Set of ordered chromosomes.
DNA
Whitish substance. Its chains form a double helix. Each chain is formed by phosphate groups, sugars, and nitrogenous bases: adenine, guanine, cytosine, and thymine.
Genes
A DNA fragment that contains the necessary information to synthesize a protein.
Read MoreDigestive Processes: From Small Intestine to Egestion
Small Intestine: Digestion and Absorption
The small intestine is involved in chemical digestion and absorption of nutrients. It is connected with valves to:
- The stomach through the pylorus.
- The large intestine through the ileocecal valve.
The small intestine has three parts:
- Duodenum: Primarily responsible for the digestion of proteins (using trypsin), carbohydrates (using pancreatic amylase), and fats (using lipase).
- Jejunum: Focuses on food absorption. The inner layer is full of folds called villi,
Micronutrients, Macronutrients, and Balanced Diet
Micronutrients and Their Effects on the Body
Micronutrients, primarily minerals and vitamins, are essential components of a healthy diet. They perform various crucial functions:
Minerals
- Calcium: Required for bone and teeth formation. Deficiency causes osteoporosis, rickets, and retarded growth.
- Iron: Necessary for the formation of hemoglobin. Deficiency leads to anemia.
- Phosphorus: Helps in making strong bones and teeth.
- Sodium: Supports the nervous system for better response. Deficiency causes cramps
Digestive, Respiratory, and Circulatory Systems
Digestive System Accessory Organs
These organs are located outside the digestive tract, although the digestive juices they secrete are passed into it. These juices contain a great variety of digestive enzymes (proteins that accelerate the breakdown of complex food into nutrients).
- The salivary glands: Three pairs of glands that secrete saliva into the mouth.
- The liver: The largest gland. It secretes bile, which is stored in the gallbladder. Bile helps us to digest lipids by acting as a detergent. The