Notes, summaries, assignments, exams, and exercises for Biology for Secondary education

Annex 1: Categories of Controlled Waste

Wastes Containing Specific Constituents

Annex 2: List of Dangerous Characteristics

Act 6: Joint Classifications

Synovial Joint

In a synovial joint, the bones move and are lined by cartilage. Between the bones, a bursa is present, which secretes synovial fluid. The bones are wrapped in a tough, flexible tissue called the joint capsule, which prevents the bones from dislocating. Ligaments are found outside the joint capsule.

Examples include the wrist, shoulder, and hip.

Synarthrosis

These are stiff and motionless bone joints, such as those connecting the bones of the skull, known as sutures.

Amphiarthrosis

These are semi-mobile joints, mainly found in the coxal bones at the symphysis pubis and in the vertebrae. The bones are united by cartilage; between the vertebral bodies, there is a disc called fibrocartilage, which allows for...

Phylum Platyhelminthes: Flatworms

General Characteristics

• Most are hermaphroditic.
• Possess bilateral symmetry and a defined head region.
• The nervous system is present.
• Includes the parasitic tapeworm.

Movement

• Controlled primarily by longitudinal muscles.
• Some species move along slime trails.

Feeding and Digestion

• Free-Living Species: Carnivores or scavengers with a complex digestive system.
• Parasitic Species: Feed on blood or fluids; lack a digestive system, absorbing nutrients directly from the host.

Sense Organs

• Possess chemoreceptors, balance receptors, and receptors that sense water movement.
• Some species show sensory development in the head region.

Classes of Flatworms

Turbellaria (e.g., Planaria)

• Live primarily in fresh water.
• Are hermaphrodites.
• Reproduce

Human Body Systems: Circulation, Respiration, and Excretion

Pulmonary Circulation (Lesser Circulation)

In the Pulmonary Circulation (Minor Circulation), deoxygenated blood passes from the right atrium to the right ventricle and is then pumped into the pulmonary artery. This artery supplies blood directly to the lungs. In the pulmonary alveoli, where gas exchange, known as hematosis, takes place, the resulting oxygenated blood returns to the left atrium through the pulmonary veins. This completes the lesser circulation.

Hematosis: The Process of Gas Exchange

Hematosis is a vital process that occurs at the alveolar-capillary membrane. In this process, gas exchange occurs by diffusion. Specifically:

• Oxygen (O₂) that is in the alveoli passes into

Neural Pathway Components

• Integrating center: It contains neurons and analyzes information associations brought by sensory neurons to produce a response.
• Association neuron: Connects sensory and motor neurons.
• Motor or efferent neuron: The nerve impulse leads to an effector.
• Effector: This is the target of the nerve impulse (skeletal muscle, smooth muscle, cardiac muscle, or glands).

Membrane Potential Fundamentals

The membrane consists of a positively charged extracellular environment and a negatively charged intracellular environment. The electric potential of the membrane is recorded using microelectrodes.

Resting Potential

The differential distribution of charges on the sides of the membrane determines that the neuron is electrically polarized....

Characteristics of the Female Gamete

The female gamete differs from the male gamete in several key respects:

• Discontinuous production: Unlike sperm, egg production is not constant.
• Lifespan: It begins at puberty and lasts a lifetime, ending at menopause.
• Yield: Each precursor cell produces only one egg, whereas spermatogenesis yields four gametes.
• Quantity: Eggs are produced in significantly smaller numbers than sperm.

Structure of the Egg

The egg contains 23 chromosomes but possesses unique structural features:

• Morphology: The egg is a large, rounded cell.
• Motility: It is stationary, as it lacks locomotive structures.
• Nutrients: It contains reserve substances to nourish the embryo during the initial days post-fertilization.
• Protection: The egg is covered

Central Nervous System (CNS) Components and Protection

The Central Nervous System (CNS) is composed of the brain and spinal cord. It is protected by membrane layers, called the meninges, and bone structures: the skull (for the brain) and the vertebrae (for the spinal cord).

Major CNS Structures Housed in the Cranium

The brain structure housed in the cranium includes the Cerebrum, Cerebellum, and Medulla.

The Cerebrum Structure and Function

The Cerebrum is divided into two hemispheres. Its surface features include protrusions called gyri and depressions called sulci or fissures. The cerebral cortex is the outer part, made up of gray matter that receives information from sense organs, produces response orders, and stores and processes information....

The Human Reproductive System

Female Reproductive Organs

The external reproductive organs (genitals) have two functions: to allow sperm entry and to protect the genitals. Its most important parts are:

• Labia Minora and Labia Majora
• Vagina: The female organ of copulation.
• Uterus: The organ for gestation, composed of muscle tissue.

HIV Transmission Awareness

There are three primary ways HIV is transmitted:

• Direct sexual contact (without condoms).
• Contact with contaminated blood (e.g., intravenous drug use, shared syringes or needles).
• Perinatal (mother to child transmission).

Contraceptive Methods

Effective methods for preventing pregnancy include:

• Contraceptive Pill: The daily intake of a combination pill inhibits ovulation, making it one of the most effective

Mechanisms of Defense: The Immune System

The immune system consists of a set of organs, cells, and molecules dispersed throughout the body that is responsible for its defense. This defense system operates through internal and external defenses.

External Defenses

They consist of physical and chemical barriers and are the first line of defense to prevent the entry of pathogens. These barriers are mainly the skin and mucous membranes.

Internal Defenses

In the interior of the body, we can distinguish two types of defenses:

• Nonspecific Defenses

  Are so called because they do not depend on the nature of the pathogen. The most important are the inflammatory reaction and the nonspecific cellular defense:

  • Inflammatory reaction. It is a local reaction involving

Female Reproductive Anatomy

The Uterus

The uterus is a pear-shaped organ, inverted. Its walls are formed by a muscular layer lined by an epithelial layer, the uterine lining or endometrium.

The Vagina

The vagina is an elastic conduit connected to the uterus.

Sperm and Spermatogenesis

Sperm Structure

Sperm cells are tiny, highly specialized cells. The front portion, known as the head, contains the nucleus with the parental genetic material. They also have a long thread called the flagellum (or scourge).

Formation of Sperm

Sperm are formed within the testes in small tubes called seminiferous tubules. Each testis contains many seminiferous tubules inside.

Ovules and Oogenesis

Ovules (Egg Cells)

Ovules are large cells containing hereditary information and...