Male and Female Reproductive Systems Explained
Male Reproductive System
The male reproductive tract follows this path: Seminiferous Tubules, Epididymis, Vas Deferens, Ejaculatory Duct, Urethra, and Penis.
Testes and Scrotum
The testes are paired gonads suspended in the tunica vaginalis. The scrotum consists of skin, dartos muscle, superficial scrotal fascia, cremaster muscle, and tunica vaginalis. The dartos and cremaster muscles regulate testicular temperature (~35°C) for spermatogenesis. The testes are perfused by the testicular artery and drained
Read MoreHuman Anatomy and Biological Systems Reference
Nervous System (Sis. Nervios)
- Nervous System: The bodily system that transmits signals and coordinates actions of the body.
- Brain (Cervell): The large organ that controls bodily functions through the release of hormones or activating muscles.
- Motor: If a neuron is a motor neuron, it helps to create the ability to move.
- Nerve: A cordlike structure that enables the transmission of electric impulses through the nervous system.
- Network: A group of connected neurons that process information.
- Neuron: A cell
Understanding Viruses: Structure, Replication, and Biology
The Discovery of Viruses
- Dmitri Ivanovski discovered that a disease in tobacco plants was spread by liquid extracted from infected plants.
- Martinus Beijerinck named these tiny disease-causing particles “viruses,” the Latin word for poison.
- Wendell Stanley showed that viruses can be crystallized, concluding they are not truly alive.
- Viruses are defined as nonliving particles made of proteins, nucleic acids, and sometimes lipids.
Key Vocabulary
- Virus: A nonliving particle made of proteins, nucleic acids,
Purpose and content of
THE CELL CYCLE
Interphase (Preparation):
G1: Cell grows and performs normal functions
S: DNA replicates (sister chromatids are formed)
G2: Final growth and preparation for division
M Phase (Division):
Mitosis or Meiosis: Division of the nucleus
Cytokinesis: Physical division of the cytoplasm
MITOSIS: THE CLONE MAKER
Purpose: Growth, tissue repair, and asexual reproduction
Location: Somatic (body) cells
Outcome: 2 identical diploid (2n) daughter cells
Process:
Prophase: Chromosomes condense; spindle forms
Metaphase:
Read MoreHuman Anatomy and Physiology: Systems and Functions
Musculoskeletal System
Axial Skeleton
The axial skeleton consists of the skull, vertebrae, and thoracic cage, forming the main central framework of the body.
Pectoral Girdle
Made of the clavicle and scapula, this structure attaches the upper limbs to the axial skeleton at the joint between the sternum and clavicle.
Pelvic Girdle
The pelvis includes the hip bones, sacrum, and coccyx. The pelvic girdle attaches the lower limbs to the axial skeleton.
Sarcomere
The smallest unit of muscle contraction. These
Read MoreEssential Biology Concepts and Classification Principles
Biological Classification and Systems
1. Five-Kingdom Classification
Who proposed the five-kingdom system of classification?
Ans: The five-kingdom system of classification was proposed by R.H. Whittaker in 1969.
2. Kingdom Protista
Which kingdom shows a link with all eukaryotic members?
Ans: Kingdom Protista serves as a link with other eukaryotic kingdoms like Plantae, Fungi, and Animalia.
3. Commercial Use of Red Algae
What is the commercial use of red algae?
Ans: Red algae (such as Gelidium and Gracilaria)