Notes, summaries, assignments, exams, and exercises for Biology for University

Phases of Neuromuscular Transmission

Motor Neuron Transmission:

1. The action potential occurs in the axonal cone and travels along the axon (nodes of Ranvier). When it reaches the presynaptic membrane, voltage-gated Ca channels open.
2. Ca enters the neuron, and the presynaptic membrane attracts vesicles of acetylcholine (ACh) found in the axon's cytosol.
3. Acetylcholine is released into the synapse.
4. Chemical-gated channels open when coupled to ACh, allowing Na to enter the cell.
5. An action potential occurs in the muscle cell membrane and spreads throughout the plasmolemma.
6. In the triad, dihydropyridine receptors (DHPR) are close to the terminal cisternae. When stimulated by the action potential, they stimulate ryanodine receptors. Ryanodine receptors (calcium

The Human Digestive System Structure

The digestive system is made by the gastrointestinal tract and accessory glands.

The Digestive Tract

The digestive tract begins in the mouth and ends at the anus. It includes the oral cavity, pharynx, esophagus, small intestine, and the large intestine.

Accessory Glands

Accessory glands are organs that pour their secretions into the digestive tract. These include the salivary glands (producing saliva in the mouth), gastric glands (in the stomach), and intestinal glands (in the intestine). The liver and pancreas are also glands that discharge their secretions into the digestive tube.

Initial Stages of Digestion

Mastication (Chewing)

Mastication is a mechanical process that breaks food into pieces. This is done by...

Congenital Malformations of the Central Nervous System

Neural Tube Formation Defects

These defects arise from incomplete closure of the neural tube during neurulation:

• Anencephaly: Malformation of the rostral neural tube resulting in no development of the cerebral hemispheres. Differentiation occurs up to the metencephalon caudally. Characterized by the lack of the cranial vault (calvaria).
• Amyelia: Spinal Cord (SC) defect characterized by the lack of formation of the neural arch of vertebrae (also known as rachischisis).
• Myeloschisis: A severe defect in neural tube closure affecting all or part of the spinal cord. Often associated with anencephaly.
• Spina Bifida: Lack of formation of the neural arch of vertebrae, most frequently occurring in the

Hormone Action

Endocrinology studies the glands of internal secretion, responsible for producing hormones, chemical messengers that act on tissues and organs of our body. The pituitary gland is controlled by hypothalamic releasing factors, the thyroid gland secretes thyroxine, the pancreas secretes insulin, the adrenal glands secrete adrenaline and cortisone, and the gonads secrete sex hormones.

Growth Hormone (GH or STH)

Growth hormone originates in the anterior pituitary gland and is considered essential for normal growth. It is classified as anabolic while under the influence of the diencephalic hormone STH. It is specific to the species, and its rate decreases after the age of 30.

Features:

• Stimulates growth and metabolic functions.
• Stimulates

Criteria for Rheumatoid Arthritis Diagnosis

Diagnosis requires meeting 4 out of 7 criteria:

• Morning stiffness lasting at least 1 hour.
• Arthritis in 3 or more joints.
• Symmetric arthritis.
• Arthritis of the hands.
• Rheumatoid nodules.
• Positive rheumatoid factor.
• Typical radiological alterations.

Inflammatory Spondyloarthropathies

Characterized by axial skeleton and/or sacroiliac joint involvement, often with peripheral arthritis and enthesitis. HLA-B27 positivity is common.

Common Spondyloarthropathies

These inflammatory, chronic, and progressive conditions affect the sacroiliac joints and spine, leading to loss of mobility. Etiology is often multifactorial, and enthesitis is a fundamental alteration.

Subchondral Sclerosis and Osteophytes

Subchondral sclerosis...

Physiology of Diving

When organisms dive, especially without an external oxygen supply, anaerobic processes can severely impact the nervous system, potentially leading to death. However, marine mammals like cetaceans and pinnipeds have evolved remarkable adaptations that allow them to undertake deep and prolonged dives.

• Oxymyoglobin

  A muscle pigment that significantly increases oxygen storage capacity within muscles. This oxygen is obtained from oxyhemoglobin in the blood, providing a localized oxygen reserve.

• Vasoconstriction and Bradycardia

  Vasoconstriction involves the constriction of veins and arteries, redirecting blood flow primarily to essential organs like the heart and brain. This is complemented by bradycardia, which slows the heart rate,

Blood Components

Platelets

Platelets are tiny specialized cells that are activated whenever there is blood clotting or repair is needed. They are colorless and deform easily.

Blood Plasma Composition

Blood Plasma: Fluid formed by amino acids, carbohydrates, proteins, salts, lipids, hormones, antibodies, enzymes, and dissolved gases. Its two main components are water and proteins (albumin, globulin, and fibrinogen).

The Heart: Structure and Blood Flow

Heart Wall Layers

The endocardium consists of epithelial tissue lining that is continuous with the endothelium of blood vessels. The myocardium is the most voluminous layer, being composed of a special type of muscle tissue called cardiac muscle tissue. The pericardium forms the wall that surrounds the...

Epithelial Tissue: Simple Layers

• Simple Squamous Epithelium (Protection + Filtration)
  • Locations: Blood vessels, lymph vessels, Bowman's capsule, inner surface of the tympanic membrane, endocardium, pulmonary alveoli.
• Simple Cuboidal Epithelium (Secretion + Absorption)
  • Locations: Ovarian surface, posterior surface of the lens, renal tubules.
• Simple Columnar Epithelium
  • Non-ciliated: Digestive tract (stomach to anus), microvilli, ducts of mucous glands.
  • Ciliated: Upper respiratory tract, Fallopian tubes, ependyma, paranasal sinuses.
  • Function: Performs and receives stimuli, movement (cilia), cough, and sneezing.

Epithelial Tissue: Stratified Layers

• Stratified Squamous Epithelium
  • Keratinized: Skin.
  • Non-keratinized: Mouth, esophagus, epiglottis.
• Stratified

Cancer: Molecular Basis and Tumor Characteristics

Tumor Types and Characteristics

Cancer involves molecular alterations that generate cells with a selective advantage. These can manifest as:

• Benign Tumors: Abnormal cells grouped into a single mass.
• Malignant Tumors: Abnormal cells with the ability to spread to surrounding and distant tissues. These tumors are considered carcinogenic.

Invasion and Spread

The ability of malignant cells to invade tissues far from the origin through the bloodstream or lymphatic vessels is called metastasis.

Cancer Classification by Tissue Origin

Cancers are classified based on their tissue of origin:

• Carcinoma: Originating from epithelial cells.
• Sarcomas: Originating from muscle or connective tissue cells.
• Cancers not derived

1. An example of an organic compound would be: CH4.

2. Which of the following would not be an organic molecule? WATER

3. The measurement of the concentration of hydrogen ions compared to the concentration of hydroxide ions in a solution is called: pH.

4. The waste products of cellular respiration include: WATER AND CARBON DIOXIDE.

5. Matter is anything that: HAS MASS AND TAKES UP SPACE.

6. When an overwhelming body of observations and measurements supports a scientific hypothesis or group of related hypotheses, it becomes a: SCIENTIFIC THEORY.

7. Which of the following statements is a correct distinction between autotrophs and heterotrophs? ONLY AUTOTROPHS CAN LIVE ON NUTRIENTS THAT ARE ENTIRELY INORGANIC.

8. What happens to all the energy you expend?...