Science

• Endocrine System


  Group of organs called "Endocrine Glands"
• Gland


  Smallest living unit in the body that produces and releases a chemical substance called "Hormones"
• Overall Role of the Endocrine System

  • Consists of many glands which secrete hormones directly into the bloodstream to regulate daily activities of the body and control its overall development
  • Hormones act as chemical messengers in the body which stimulate many organs
  • Also known as "System of Checks and Balances" that works to keep the body system healthy
  • Turns on and off in response to the level of hormones in the body
  • When not properly doing its job, the overall health of the body may be affected
• Endocrine Glands


  • Hypothalamus
  • Pituitary
  • Adrenal
  • Thyroid
  • Parathyroid
  • Pancreas
  • Thymus
  • Ovaries
  • Testes
• Hypothalamus Gland


  • Hormones: Releasing Factors, Oxytocin, Antidiuretic Hormone (ADH)
  • Function and Location: Connected to the pituitary gland by blood vessels to regulate body temperature, blood pressure and use of water. It is a small gland located at the base of the brain. It regulates activities of the body, metabolism, and reproduction. ADH increases water uptake in the kidney. The hormone released from the hypothalamus is to control muscle contractions of uterus and milk production.
• Pituitary Gland


  • Hormones: Adrenocorticotropic Hormone (ACTH), Thyroid Stimulating Hormone (TSH), Growth Hormone, Prolactin
  • Function and Location: It Stimulates adrenal gland to release specific hormone. It stimulates thyroid gland to release specific hormones. It regulates growth of skeletal system. It Stimulates milk production in mammary glands.
• Adrenal Glands


  • Hormones: Adrenaline (epinephrine), Aldosterone
  • Function and Location: Controls "fight or flight" response. The adrenaline hormone is released into the blood stream when a person has a fright. Found just above the kidney. Produces specific hormones that affect the the kidneys, metabolism, and response to stressful situations. Secretes both male and female sex hormones in both sexes. Increases uptake of sodium and water in the kidney.
• Thyroid Gland


  • Hormones: Thyroxine and Calcitonin
  • Function and Location: It is located at the front of the pituitary gland. It regulates of metabolism. This gland secretes thyroxine, which contains iodine and the calcitonin which controls calcium level in bloodstream.
• Parathyroid


  • Hormones: Parathyroid Hormone
  • Function and Location: Are four tiny glands connected to the back of the thyroid gland. This hormone regulates the minerals in the body calcium as well as the phosphorus in the bloodstream.
• Pancreas


  • Hormones: Insulin and Glucogen
  • Function and Location: Located beneath the stomach. The insulin controls the level of sugar in the blood. The glucogen stimulates the liver to convert glycogen to glucose. Hypoglycemia can occur if there is a low sugar in the blood.
• Thymus, Ovaries and Testes

  • Hormones: Estrogen, Testosterone, Progesterone
  • Function and Location: Located in the upper chest of the heart. Plays an important role in developing some of the body's defenses against infection. These play an important role in reproduction.
• Homeostasis


  • Responsible in the regulation and maintenance of the internal environment of the body
  • Regulates body temperature, fluids, salts, acids, gases, and nutrients that help support humans life
  • Internal control system of the body responds immediately to change from the different conditions or internal environment
  • There are different control systems in the body-sensors, control center, communicating system and targets
• Parts of the Nervous System

  • Central Nervous System (CNS) - brain and spinal cord
  • Peripheral Nervous System (PNS) - nerves that extend throughout the body
• Endocrine System


  • Communicates using chemical messengers called hormones
  • Hormones are produced by various glands, including the thyroid, adrenal glands, and pituitary gland, and are released directly into the bloodstream
  • The effects of hormones are generally slower and more long-lasting
• Components of the Control System

  • Sensors - receptors responsible for gathering information about conditions inside and outside the body
  • Control Center - the brain, part of the nervous system
  • Communicating System - the nervous system and endocrine system
  • Targets - organs, tissues, or cells responsible for changes in body activity
• Major Functions of the Nervous System

  • Sensory Input - information/signals from sensory organs
  • Integration - brain's process of combining and interpreting information
  • Motor Output - signals/commands from brain and spinal cord to muscles and glands
• Parts of a Neuron

  • Dendrites - branched cell components that receive stimulus
  • Cell Body - contains nucleus that processes stimulus
  • Axon - transmits stimulus to target
• Target Cell Response to Hormones

  • Different types of hormones secreted by endocrine glands are directly diffused into the bloodstream
  • Only target cells have receptors to which the specific hormone can bind
  • The "lock and key" mechanism, with hormones as the key and receptors as the lock
  • The response occurs when the hormone and receptor bind, triggering the target tissue
• Feedback Mechanisms in Regulating Processes in the Female Reproductive System

  • The nervous system and endocrine system play an important role in the feedback system
  • Hormones and nerve cells regulate movement during labor contractions
  • Feedback regulation can be either positive or negative
• Negative Feedback


  • A control system that serves to reduce an excessive response and keep a constant set point
  • The set point is the physiological value around which the normal range fluctuates
  • Negative feedback is a mechanism that regulates homeostasis by reversing change to return the body to normal conditions
• Positive Feedback


  • The secretions of hormones from the endocrine glands are under the control of the hypothalamus, which is also controlled by negative feedback
  • Positive feedback loops maintain a state of balance by reinforcing change to move the body further from normal conditions
• An example of a negative feedback mechanism is the regulation of blood glucose levels by insulin
• Protein


  • A varied molecule that the human body contains at least 10,000 different kinds of
  • They are large and very complex, and do most of the work in cells
• Functions of Proteins


  • Antibody - holds specific particles to protect the body
  • Enzyme - carries out chemical reactions and assists with new molecule production by reading genetic information in DNA
  • Messenger - hormones that transmit signals to coordinate biological processes
  • Structural Components - allow the body to move and support cells
  • Transport/Storage - carry atoms and molecules throughout the body
• Amino Acids


  • Essential - those the body cannot produce and must be obtained from the diet
  • Non-essential - those the body can produce on its own
• Importance of Proteins


  • Protein hormones regulate many physiological processes, like insulin affecting glucose transport
  • Protein in the blood helps as a blood clotting factor and transport molecule, like hemoglobin transporting oxygen
  • Protein acts as ion channels, carriers, and receptor molecules in the cell membrane
• Essential Amino Acids


  • Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine
• Non-Essential Amino Acids


  • Alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, proline, serine, tyrosine
• Nucleic Acid


  • A large molecule composed of carbon, hydrogen, oxygen, nitrogen and phosphorus
  • The building blocks of living organisms
  • Comes in 2 main types: DNA & RNA
• Nucleotides


  Building blocks of nucleic acids, consisting of a phosphate group, a sugar, and a nitrogen base
• DNA


  • Has 2 strands of nucleotides joined together to form a twisted "double helix" molecule
  • The double helix structure is due to the specific linking of its nitrogenous bases: adenine (A) with thymine (T) and cytosine (C) with guanine (G)
• RNA


  Contains the sugar ribose, unlike DNA which is double-stranded, RNA is single-stranded
• Kinds of RNA in Protein Synthesis

  • Messenger RNA (mRNA) - travels from nucleus to ribosomes, acts as messenger between DNA and protein production
  • Ribosomal RNA (rRNA) - component of ribosomes, provides mechanism for decoding mRNA
  • Transfer RNA (tRNA) - adaptor molecule that brings amino acids to ribosomes
• Genetic Code


  The instructions included in a gene that direct a cell's production of a particular protein
• Codons


  Groupings of three nucleotides that make up the genetic code
• DNA Polymerase


  Essential enzyme in DNA replication, responsible for accurately transmitting genetic information
• DNA Replication


  1. Occurs in the nucleus of eukaryotic cells, or the cytoplasm of prokaryotic cells

  2. Happens before cell division so new cells get a copy of DNA

  3. Involves 4 enzymes: DNA Polymerase, Helicase, Primase, and Ligase
• Transcription


  1. The process of copying the genetic information from DNA's nucleotide sequence into messenger RNA (mRNA)

  2. Main objective is to transport the DNA's genetic code to the ribosomes outside the nucleus where proteins can be produced
• Translation


  The process that takes the information passed from DNA to mRNA and uses it to produce proteins
• Transcription


  1. Genetic information from DNA's nucleotide sequence is copied into messenger RNA (mRNA)

  2. To transport the DNA's genetic code to the ribosomes outside the nucleus where it can produce proteins through the mRNA