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

Genome

Sense of Smell: Enables the body to detect chemical molecules in the air. Molecules are detected by chemoreceptors in the nasal cavities. Sensations they receive are called smells.

Types of Nasal Mucous Membranes:

• Respiratory Mucous Membrane: Has blood vessels that warm inhaled air and hairs that trap dust particles.
• Olfactory Mucous Membrane: Contains the olfactory receptors. Chemoreceptors converge in the olfactory bulb. Receptors transmit impulses along the olfactory nerve to the brain when stimulated by chemicals.

Sense of Taste: Enables the body to detect flavors. Four basic tastes: sweet, salty, sour, and bitter. Chemoreceptors respond to chemicals dissolved in saliva, located mainly on the tongue, but also on the palate, pharynx, and larynx....

Anatomical Changes in Human Evolution

Anatomy is the scientific study of the structures of living things, including their systems, organs, and tissues.

Bipedalism: The Upright Stance

Bipedalism first appears with Australopithecus. Due to a climate change, the jungle turned into grassland, necessitating walking upright to see over the grass. This process required many transformations:

• The legs became longer.
• The arms became shorter.
• The hands were freed.
• The pelvis became narrower.

Encephalization: Brain Enlargement

Encephalization is the progressive enlargement and increasing complexity of the hominid brain. This change is due to the expansion of the cranial cavity.

Changes in Hand Structure

The palm became shorter and the fingers became longer. Hominids...

The Human Heart: Structure and Function

The heart is a muscular organ situated between the lungs, slightly to the left. Its walls, known as the myocardium, are responsible for pumping blood.

It is made up of four chambers:

• Two atria (upper chambers)
• Two ventricles (lower chambers)

The heart also contains valves that regulate blood flow:

• The tricuspid valve connects the right atrium and the right ventricle.
• The mitral valve connects the left atrium and the left ventricle.

Understanding the Cardiac Cycle

The cardiac cycle is the sequence of events that occurs with each heartbeat. As the heart beats, it circulates blood through the body's pulmonary and systemic circuits.

There are two main phases of the cardiac cycle:

• Diastole Phase: The heart ventricles

Ovaries:

• Composed of ovarian follicles (sac-like structures)

Gametes

produced by gonads

Uterus:

• Located between the urinary bladder and rectum
• 3 layers: 1. Endometrium 2. Myometrium 3. Perimetrium
• Functions of the uterus:
  • Receives / retains a fertilized egg
  • Nourishes the fertilized egg

Penis:

• Delivers sperm into the female reproductive tract
• Regions:
  • Shaft
  • Glans penis (enlarged tip)
  • Prepuce (foreskin)
• Internally 3 areas of spongy erectile tissue around the urethra

Ovulation:

when the egg is mature the follicle ruptures

Haploid:

1N

Oocyte:

The oocyte is viable for 12 to 24 hours after ovulation

Sperm:

are viable for 12 to 48 hours after ejaculation

• Sperm cells must make their way to the uterine tube for fertilization to be possible

Fertilization:

When sperm nucleus...

Human Tissue Types and Skeletal Components

Muscle Tissue

• Muscle tissue: Cells that can contract.
• Skeletal muscle: Moves bones.
• Smooth muscle: Involuntary muscles found in the digestive system and blood vessels.
• Cardiac muscle: Makes up the heart.

Nervous Tissue

• Nervous tissue: Made of cells that receive and transmit messages.
• Neurons: Specialized nerve cells.

Epithelial and Connective Tissue

• Epithelial tissue: Layers of cells that line internal and external body surfaces.
• Connective tissue: Binds, supports, and protects structures in the body.
• Matrix: Intracellular substance that holds cells in tissue.

Body Cavities

• Cranial cavity: Contains the brain.
• Spinal cavity: Holds the spinal cord.
• Thoracic cavity: The upper part of the torso.
• Abdominal cavity: The lower

The Human Sensory System: Receptors and Organs

Understanding Sensory Receptors

Sensory receptors are specialized structures responsible for detecting changes (stimuli) in the world around us and converting them into nerve impulses. These impulses then travel to a higher nerve center where perception begins. Sensory receptors can be simple groups of nerves or, more often, special cells that join together to form the sensory organs.

Classification of Sensory Receptors

Receptors are typically classified based on the type of stimulus they detect:

• Photoreceptors: Detect light stimuli and are found in the eyes.
• Mechanoreceptors: Stimulated by changes in movement, such as pressure, contact, or sound waves. These include receptors in the skin, muscles, and

Development of Cancer

• Oncogenes are transformed by carcinogens.
• Cancerous cells do not respond to signals from other cells, so they continue to divide (rapid mitosis).
• Cancerous cells are not removed by the immune system.
• The tumor gets bigger.
• Cells change their characteristics and look different under the microscope.
• The tumor is supplied with blood and lymph vessels.
• Tumor cells spread in blood and lymph to other parts of the body (Metastasis).
• Secondary cancers form throughout the body as tumor cells invade other tissues.

Protein Synthesis

Transcription

The double helix of the DNA is unwound by RNA Polymerase, which docks on the DNA at a special sequence of bases. RNA Polymerase moves downstream, unwinding the DNA. As the double helix unwinds, ribonucleotide...