Untitled

• The material covers Science, specifically focusing on Unit 3, which deals with "Living Things and Their Environment".
• The book was developed and reviewed by educators from various schools, colleges, and universities, and feedback is welcome
• The material is owned by the copyright holders, with DepEd represented by FILCOLS in seeking permission for use
• Reproduction of the Learner's Material is restricted to institutions with agreements with FILCOLS
• Authors and publishers should be contacted directly for copying permissions especially those without affiliated partnerships

Table of Contents Overview

• Unit 3 is about Living Things and Their Environment
• Module 1: Coordinated Functions of the Nervous, Endocrine, and Reproductive Systems
• Module 2: Heredity: Inheritance and Variation
• Module 3: Biodiversity and Evolution
• Module 4: Ecosystem: Biodiversity

Unit 3 Introduction

• Modules enable you to apply science concepts and inquiry skills in addressing world problems through scientific investigations
• Instructional activities are designed to enhance knowledge, understanding, skills, and ability to transfer learnings
• By the end of Grade 10, scientific, technological, and environmental literacy should already be developped

Module 1: Coordinated Functions of the Nervous, Endocrine, and Reproductive Systems

• Time allotment is 12 to 14 hours.
• If any part of these organ systems malfunctions, the body will become unbalanced
• The instability caused by the malfunctioning of one system cannot be made stable by other systems
• In Grade 9, you have already studied how the circulatory and respiratory systems work together and how lifestyle affects these systems
• Now you will learn about the coordinated functions of the reproductive, endocrine, and nervous systems.
• This modules helps understand organisms having feedback mechanisms, coordinated by the nervous and endocrine systems
• These feedback mechanisms help organisms maintain homeostasis to reproduce and survive.

Learning Competencies/Objectives for Module 1

• Describe the parts of the nervous, endocrine, and reproductive systems, and their functions
• Explain the role of hormones involved in the female and male reproductive systems
• Describe the feedback mechanisms in regulating processes in the female reproductive system
• Describe how the nervous system coordinates and regulates feedback mechanisms to maintain homeostasis

Key questions addressed in Module 1

• How do the nervous, endocrine, and reproductive systems perform coordinated functions?
• How do hormones regulate various mechanisms inside the human body?
• How do feedback mechanisms help organisms maintain homeostasis in order to reproduce and survive?

The Nervous System

• Connects all body parts and transmits signals, regulating body's responses to stimuli
• Each part has specific roles as important part of a system called Central Nervous System (CNS).
• The CNS is the main processing center consisting of the brain and spinal cord.
• Peripheral Nervous System (PNS) connects the CNS to organs and limbs, with somatic and autonomic divisions.
• Brain consists of three parts: Cerebrum, Cerebellum, and Brain Stem
• Spinal Cord is a channel for signals between the brain and the rest of the body, and controls simple musculoskeletal reflexes
• Autonomic Nervous System is associated with involuntary control of body movements and has two subdivisions: Sympathetic, and Parasympathetic

Nerve Cells (Neurons)

• The basic unit of the nervous system
• Billions of these nerve cells present in each neural network
• Each neuron consists of a cell body containing the nucleus.
• Projecting out from the cell body are root-like structures. These are the dendrites and axons
• Dendrites carry impulses toward the cell body and axons carry impulses away from the cell body
• Axons pass impulses to the dendrites of other neurons or cell body of muscle cells
• Axons can be grouped together into cable-like bundles called nerves
• Neurons are cells with the special ability to carry signals or impulses that are electrochemical signals moving along a neuron
• There are twelve to fourteen billions of neurons in one part of the brain alone
• A single dendrite can be over one meter long.
• A nerve impulse cannot jump from one neuron to another
• When a nerve impulse comes to the end of an axon, it produces the chemical, called neurotransmitter, to be released
• The chemical crosses the space between neurons called synapse and stimulates the nerve impulse to start in the next dendrite
• The nervous system is assisted with five sense organs the eyes, ears, nose, tongue, and skin
• These sense organs are constantly receiving information from the environment and sending messages to the brain
• The Senses contribute in the survival of human beings. A stimulus is any factor in the environment that may trigger a nerve impulse
• A response is reaction to a stimulus and an organism must be able to respond to stimulus to survive
• Reaction time is the length of time between application of a stimulus and detection of a response
• The spinal cord transmits information through the spinal cord, which extends from the brain down through the back and consists of fine nerves that branch out to every organ and body part
• When a message reaches the brain from any part of the body, the brain commands the body to respond
• Motor neurons transmit impulses from the brain to muscles, glands, or other neurons
• Sensory neurons transmit impulses from sensory nerves (receptor cells) to the Central Nervous System (CNS).

Endocrine System

• Controls and regulates body processes that slowly take place such as body cell growth
• Endocrine system works together with the nervous system to enable the body to function properly
• Endocrine system is composed of glands that secrete different types of hormones affecting cells, organ, and body function
• Endocrine system is essential in reproduction, regulating growth and development, metabolism, as well as processes and mood
• Endocrine glands secrete chemicals known as hormones into the bloodstream, which carries them throughout the body
• When a hormone in the blood reaches the target organ, it produces a notable effect
• The endocrine system sends signals all over the body, much like the nervous system, but the effects can take a few hours or even weeks compared to the nervous system
• Hormones affect various processes in the body as they regulate and balance the functioning of organs, tissues, and cells
• Hormones have great impact on your growth, appearance, emotions, and reproductive functions
• Hormones determine whether or not you develop disorders such as diabetes, thyroid disease, growth disorders, or sexual dysfunction
• Hormones act in very small amounts. An increase or decrease in hormonal levels may result in body disorder due to hormonal imbalance.
• Hormonal imbalance this condition is considered an abnormality

Endocrine Glands and Their Hormones

• Pituitary gland stimulates growth and controls the functions of other glands. Hormones: Oxytocin, Vasopressin, Growth Hormone, Adrenocorticotropic Hormone (ACTH), Prolactin, Luteinizing Hormone, Follicle Stimulating Hormone
• Thyroid regulates body metabolism, and causes storage of calcium in bones. Hormones: Thyroxin, Calcitonin
• Parathyroid controls the calcium levels in your body, and normalizes bone growth. Hormone: Parathyromone
• Thymus enables the body to produce certain antibodies. Hormone: Thymosin
• Adrenal prepares the body for action, controls the heart rate and breathing in times of emergency. Hormone: Adrenaline
• Pancreas Regulates blood sugar levels. Hormones: Insulin, Glucagon
• Reproductive (Testes) control maturation and male characteristics. Hormones: Androgen, Testosterone
• Reproductive (Ovaries) influence female traits, and support reproductive function. Hormones: Estrogen, Progesterone

Reproductive System

• Involved in sexual reproduction
• Striking differences exists between male and the famle reproductive system
• Reproductive system depends on reproduction survival for the species
• The release of semen can be regulated by hormones or special chemicals, and those hormones keep the reproductive system properly functioning
• The pituitary gland controls gland controls the function of the of the testes of the male and female reproductive system.
• The follicles produce hormones that control the growth and release eggs from the ovaries. While other Hormones prepare the uterus so a baby can grow in it, other Hormones still control the stretching of the uterus during pregnancy
• When a female reaches puberty, egg cells start to develop in her ovaries that produce the sex cells
• A negative feedback affects the production of hormones in the menstrual cycle with high levels of one hormone that inhibit the production of another hormone

Feedback Mechanisms in Female & Male Reproductive Systems

• Hormones control changes in the reproductive system.
• Monthly changes in the female reproductive system are called menstruation
• The pituitary gland releases hormones that cause the egg in the ovary to mature.
• Luteinizing hormone (LH) initiates maturation of the follicles, converts ruptured follicles into corpus luteum and causes the secretion of progesterone.
• Follicle stimulating hormone (FSH) assists in maturation of the follicles and causes the secretion of estrogen from the follicles.

Homeostasis

• Achieved through regulation of bodily functions by endocrine and nervous systems
• Most body systems maintain homeostasis via feedback mechanisms.
• Levels of hormones body are controlled by feedback at the right level needed
• Nervous and endocrine systems maintain normal ranges for: Body temperature, Amount of water in the body, Metabolic wastes in the cell, Blood calcium level, and Hormone levels