Science 3rd Quarter Reviewer - Grade 10 PDF

**SCIENCE 3^RD^ QUARTER REVIEWER** **LESSON 1: NERVOUS SYSTEM** **BIOLOGY** -- Study of living organisms. **\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\...

**SCIENCE 3^RD^ QUARTER REVIEWER** **LESSON 1: NERVOUS SYSTEM** **BIOLOGY** -- Study of living organisms. **\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--** **Morphology** - deals with the form of living organisms, and with relationships between their structures. **Botany** - deals with the study of plants, including their structure, properties, and biochemical processes. **Genetics** - deals with the heredity and variation of organisms. **Zoology** - deals with the study of animal life ranging from the structure of organisms to its subcellular life. **Ecology** - deals with the relations of organisms to one another and to their physical surroundings. **NERVOUS SYSTEM** - It is a **network of cells and tissues** that controls thoughts, movements, as well as life processes **including breathing, walking, thinking, and feeling**. - Functions like **Central Processing Unit (CPU)** - It serves as the **center of all mental activities** including learning, memory, thinking, and speech. - It **receives**, **examines**, and **process data** and initiates appropriate **responses**. - It **controls** and **regulates** **all activities** within the human body. - It **coordinates** **and functions** of all the other **organs** in the body. - It **regulates** and **maintains homeostasis** with the help of endocrine system. - It **keeps us touch** with the **external** **environment**. Our Nervous System is made up of our: **(3)** - **Brain** - **Spinal Cord** - **Nerve cells/Neurons** **STIMULUS** - Anything that evokes a person's reaction. Something that causes our part of the body to react. **HOMEOSTASIS** - The body's ability to maintain constant internal equilibrium by adjusting its physiological process. **NEURON** - The **basic cellular unit** of nervous system. - It transmit impulses to and from various part of the nervous system. - Neurons are considered to be the "**messengers of the nervous system**". - They are **responsible for storing the information and carrying messages** within the nervous system and between other body systems. **THREE TYPES OF NEURON** - **Sensory neurons** -- also called as "**afferent**" neurons. **Responsible for receiving information** and **send impulses** to the **spinal cord or the brain**. - **Motor neurons** -- also called as "**efferent**" neurons. **Conduct impulses** from the brain or the spinal cord to muscles or glands throughout the body. - **Interneurons** -- **Relay impulses or information** from the sensory neurons to the motor neurons. **STRUCTURE OF NEURON** - **Dendrites** receive signals. - The **cell body** integrates signals. - The **axon** transmits action potential. The **myelin sheath** makes the signal travel faster. - **Synaptic terminals** transmit signals. - **Neurotransmitters --** Certain chemicals help in transporting the messages. **dendrites -- soma -- axon -- synaptic terminals** **TRANSMISSION OF NERVE IMPULSES** - An **axon** splits into multiple branches upon approaching a synapse. - **Branches** terminate into a synaptic knob connected to another axon, dendrite or cell body. - **Neurotransmitters** then define the movement or action to be done by the impulse. **REFLEX -** The sensory receptors in your skin responds to the hot pan by sending an impulse to your spinal cord.  **CENTRAL NERVOUS SYSTEM ** - Consists of **brain** and **spine** - **Stores memory and giving responses.** **Functions**: - Receives sensory signals and determines appropriate response - Stores memory - Carries out thought **Composition of the Central Nervous System** - **BRAIN -** An organ that performs different functions such as: memory, judgment, and reason. - **SPINAL CORD -** It bridges impulses between the brain and the body. **3 PARTS OF THE BRAIN** **COMPLEX BRAIN** - The mammalian brain is highly complex, containing many specialized regions that carry out specific functions. - Generally, the brain is divided into **hindbrain**, **midbrain**, and **forebrain**. **HINDBRAIN ** - **Medulla Oblongata --** responsible for maintaining an upright position and regulating most **involuntary** functions such as breathing and circulation. - **Cerebellum --** Coordinates fine muscle movements and balance. Small brain, balance. - **Pons --** It serves as the bridge to the midbrain. It is responsible for **sleep** regulation. **MIDBRAIN - CONNECTS HINDBRAIN TO FOREBRAIN** **Reticular formation** - It **relays signals,** particularly those coming from the eyes and the ears, to the cerebellum. - It is responsible for the general levels of lethargy or liveliness. **FOREBRAIN** - **Cerebrum** (cerebral cortex) -- It is **the seat of intelligence**; it is responsible for one's thinking, learning, emotions, consciousness, and voluntary movements. - **Thalamus** -- It sorts and relays incoming and outgoing information to the different parts of the brain. Sorting information from the midbrain to forebrain. - **Hypothalamus --** It **monitors pleasurable activities** such as eating and drinking. It influences the endocrine system in secreting hormones. **PERIPHERAL NERVOUS SYSTEM** - Nerves, neurons, and sensory organs outside the central nervous system **Functions**: - Sends signals to the CNS - **Receives** and transmits motor signals from the CNS - Stimulates effectors **2 PARTS OF THE PNS** **SOMATIC NERVOUS SYSTEM** - Motor neurons that control **voluntary movements** by activating skeletal muscles. - Not all muscles are controlled. **AUTONOMIC NERVOUS SYSTEM** - Motor neurons that control **involuntary responses** involving the organs, glands, and smooth muscles. - Controls heart, lungs, digestive system. **2 GROUPS OF AUTONOMIC NERVOUS SYSTEM** 1. **SYMPHATETIC NERVOUS SYSTEM -- Initiates "fight-or-flight" reaction. in preparing the body for stress-related activities.** 2. **PARASYMPATHETIC NERVOUS SYSTEM** -- Referred as "**rest and digest**" system as it functions to conserves the body natural activity. Brings back the homeostasis. **ENDOCRINE SYSTEM** - Initiates body activities - The endocrine system is a **chemical messenger** **system** comprising feedback loops of the hormones released by internal glands of an organism directly into the **circulatory system**, regulating distant target organs **FUNCTIONS:** - Secrete hormones into the bloodstream that controls activities such as metabolism, reproduction, growth, and development of human body. **Hormones** - chemical substances that act like messenger molecules in the body. These are produced by glands. **NEGATIVE FEEDBACK MECHANISM** - The endocrine glands send information back and forth within itself in order to control and regulate the amount of hormones it produces.' 1. The gland sends hormone to its target cell. 2. Once the target cell responded to the hormone, it sends chemical signals back to the gland to stop or slow down hormone production. 3. When the hormone level in the blood drops, the gland will secrete hormones again  **LESSON 2: REPRODUCTIVE SYSTEM** **REPRODUCTION** -- It is a biological process in which new individuals are produced in order to perpetuate the species. **THE HUMAN REPRODUCTIVE SYSTEM** The human reproductive system may be classified into two: 1. **Male Reproductive System** 2. **Female Reproductive System** **THE MALE REPRODUCTIVE SYSTEM** - Secretion of the male sex hormones - Production of sperm cells - Release of sperm cells **URETHRA -** It is a tube that carries the urine and sperm out of the body. **SCROTUM -** It is a bag of skin that holds and helps to protect the testicles **BLADDER -** It serves as a urine storage. **PENIS -** The male external **genital organ of the male** carrying the duct for the transfer of sperm during copulation. **PROSTATE -** It produces a milky alkaline fluid that activates the sperm. **COWPERS GLAND -** It produces the lubricating effect for sperm. **1^st^ fluid na nilalabas no sperm. 2nd fluid may sperm**. **TESTIS -** It is the part in the male reproductive system that produces the sperm. **EPIDIDYMIS -** It holds the matured sperm. **SEMINAL VESICLE -** It produces a sugar-rich fluid that gives energy to the sperm. **VAS DEFERENS -** It transports the mature sperm to the urethra. **TESTOSTERONE: THE MALE HORMONE** It performs the following functions: It allows for the occurrence of the secondary sex characteristics: - Hair growth (face, armpit, genitals, chest, and other parts). - Enlargement of voice box - Deepening of voice - Development of male musculature (muscular strength) - Increased secretion of sweat and oil. **SPERM CELL STRUCTURE** a mature sperm has three main parts: - **Tail** -- propels the sperm as it swims in the fluid. - **Middle piece** -- contains the mitochondria, which provide the sperm with energy. - **Head** -- contains enzymes that break the egg's membrane and house genetic materials. **SPERM COMPETITION** When a man ejaculates, about 200-500 million sperm cells are in the semen. Only less than 1% of these reach the egg for the following reasons: a\. Millions already die in the vagina due to its acidic environment. b\. Some sperm cells lose energy along the journey. c\. Some sperm cells go to oviduct or fallopian tube which does not contain eggs. d\. Some sperm cells are blocked by the mucus covering the cervix e\. Abnormality in the sperm cell **SPERM JOURNEY** **THE FEMALE REPRODUCTIVE SYSTEM** **The female reproductive organ performs the following functions:** - Production of female sex hormones - Production of egg cells - Transfer of sperm from the male sex organ. - Protection and nourishment of developing embryo. **OVARY -** Female gonad that is responsible for producing egg cell and female sex hormones. **FALLOPIAN TUBES -** Two slender tubes that connects ovaries to the uterus and serves as the site of fertilization. **UTERUS -** A pear-shaped organ, also called as womb, which serves as a home to a developing fetus.  **ENDOMETRIUM -** The layer of tissue that lines the uterus which thicken or shed blood during menstrual cycle. **CERVIX -** The lower, narrow end of the uterus that forms a canal between the uterus and vagina. **VAGINA -** A muscular canal of female sex organ that plays a huge role during sexual intercourse, menstruation, pregnancy, and childbirth. **EGG CELL JOURNEY**  Similar to males, females also secrete **follicle-stimulating hormones (FSH) and luteinizing hormone (LH)** as **directed by the pituitary gland during puberty**. A female experiences bodily changes even before the **first menstruation** (**menarche**). These are: - Development of breast - Growth of axillary and pubic hairs - Rounded body contours - Widening of hips - Development of high-pitched voices. **THE MENSTRUAL CYCLE** - **The monthly cycle of changes in the ovaries and the lining of the uterus (endometrium)**, starting with the preparation of an egg for fertilization. **MENSTRUAL HORMONES** **Anterior Pituitary** **Follicle-stimulating hormone (FSH)** - Stimulates follicular growth in ovaries. - Stimulates estrogen secretion from developing follicles (small sac containing eggs). **Luteinizing hormone (LH)** - Surge causes ovulation - Results in the formation of a corpus luteum. (a structure formed as a mature egg pops out of a follicle) - Triggers corpus luteum to secrete progesterone **Ovaries** **Estrogen** - Thickens endometrium. - Stimulates the pituitary gland to release LH causing ovulation. - Stops FSH being produced so that only one egg matures in a cycle. **Progesterone** - Thickens endometrium - Inhibits FSH and LH (luteal phase) **MENSTRUAL CYCLE** Menstrual cycle varies in women but having an average of **28 days**. **Two synchronized process:** - The Ovarian Cycle - The Uterine Cycle **THE OVARIAN CYCLE** The **series of changes** that occur in the **ovary** during the menstrual cycle that cause **maturation of a follicle**, **ovulation**, and development of the **corpus luteum**. **1.** At the beginning of the cycle, the **pituitary gland** secretes increased **amounts of FSH** and allows an **ovarian follicle to mature**. **2. Increased level of estrogen** in the blood induced the pituitary gland to **secrete luteinizing hormone (LH)** which bring the follicle's final maturation. 3\. **Ovulation**, released of a mature egg, occurs on the **fourteenth day of the cycle**. The egg is viable for fertilization with **24 hours** from its release. 4\. The cells of a ruptured follicle develops into a yellow body called ***corpus luteum** which produces more estrogen and another female sex hormone, progesterone*. Both hormones **prepare the uterine wall** for possible implantation of fertilized egg. **5.** If **no fertilization** occurs, the **amount of FSH and LH drop** which will lead to the deprivation of corpus luteum and **influence the progesterone level on the endometrial wall**. **THE UTERINE CYCLE** It governs **the preparation and maintenance of the lining of the uterus** (womb) to receive an embryo. It includes the **increase in the endometrium** in preparation for implantation and the **shedding of the lining** following lack of implantation. Prep for pregnancy. While events take place in the ovary, a series of hormone-influenced changes also happens in the uterus. 1\. **With the low level of progesterone**, the surface of endometrium begins to **disintegrate** and the **blood vessels ruptures**. 2\. Blood and some accompanying endometrial tissues flow out of the vagina in a process called *menstruation*. The *menstrual phase* last for about **five days**. 3\. **Proliferative phase** -- the **endometrium build up** due to the **increasing amount of estrogen** by the developing follicles in the ovary. Usually happens during **day 6 to 14.** 4\. **Secretory phase** -- the uterine glands **become mature and produce a thick secretion** and happens during the **fifteenth day** until before the onset of next menstrual phase. However, this cycle may be interrupted by stress, health problems, and pregnancy.  **HORMONE FEEDBACK AND PREGNANCY** When a sperm cell successfully penetrates the egg, their nuclei fuse and a ***zygote***, or fertilized egg, is formed. - **Fertilization** -- sperm's and ovum's nuclei unites. It takes place while the egg is travelling along the oviduct or fallopian tube to the uterus. It takes about **seven to ten days** for the fertilized egg to the uterus. Upon successful implantation of a developing embryo in the endometrium, it forms a special organ called **placenta**. This provides for the embryo and secrete nourishment a hormone called **human chorionic gonadotropin** (HCG). HCG acts in **maintaining the structural and functional integrity of the corpus luteum** which allows the uterine wall not to break down. **HCG** passes in the urine. It is the same hormone detected in **pregnancy test**. Thus, it is necessary for a successful pregnancy. If the **embryo has abnormalities or dies**, **HCG will drop** and the **endometrium will disintegrate**, causing a woman to have **miscarriage**, which **results in bleeding**. **From my notes:** **4 PHASES OF MENSTRUAL CYCLE** 1. **Menstrual Cycle (day 1-5)** 2. **Proliferatiive Phase -- endometrium starts to thicken. (day 6-13)** 3. **Ovulation (day 14)** 4. **Secretory Phase/Luteal Phase (day 15-28)** Progesterone -- thickens endometrium Fertile window -- day 12-15 Corpus luteum = gives progesterone to thicken 5 red days.