Lesson 2: Organ Systems of the Body

Question 1

Integumentary System

Answer 1

• Consists of a single organ: the integument (skin)
• Large and heavy organ, account for 16% of overall body mass
• Enormous number of appendages to the skin that are coupled with glands to allow this system to do its job

Question 2

Integument (Skin)

Answer 2

• Task of keeping stuff in, while keeping stuff out
• Provides a flexible structure to surround bones, muscles, and visceral organs
• Provides a waterproof physical barrier, preventing most chemicals and pathogens from entering deeper into our bodies
• Offers protection from ultraviolet radiation
• Flexibility allows energy from a physical shock to disperse, protection from sharp objects because the skin is able to compress and stretch away from objects with limits
• Important role in temperature regulation
• Body’s largest sensory organ, with receptors that tells us a great deal about our environment, sending information about pain, pressure, touch, texture, vibration and temperature to the nervous system

Question 3

Oil Glands

Answer 3

• Natures moisturizer, providing a lubricating and waterproofing layer on the surface of the skin

Question 4

Sweat Glands

Answer 4

• Can provide evaporative cooling, which helps to maintain relative constancy in body temperature

Question 5

Nails

Answer 5

• Important appendages to the skin, ideally located to protect our digits from some of the damage that might result from their being distal to the mass of our bodies
• Tougher than our skin
• Not only offer greater resistance to penetration, also distribute the energy from a shock or blow to the nail surface over a wider area, lessening the potential to do damage to the nail itself, the nail bed underneath it or to the still-deeper bones of the toes and fingertips

Question 6

Skeletal System

Answer 6

• Provides the structure that prevents us from collapsing
• There are 206 named bones in the body
• There are variations in the number of bones from person to person
• Provides a protective covering for some of our vital organs
• Production of some blood cells, which occurs within the marrow

Question 7

Cartilage

Answer 7

• Serves to cushion and connect bones

Question 8

Ligaments

Answer 8

• Found at the junction of bones, connect those bones to form joints and allow for articulation of those joints, without such joints we’d be unable to move

Question 9

Bones

Answer 9

• Are always mineralizing or demineralizing as they serve as a reserve for calcium and phosphorus

Question 10

Blood Calcium

Answer 10

• Is critical for the normal function of nerves and muscles
• A specific hormone promotes the removal of calcium from bone tissue which causes blood calcium levels to rise
• When blood calcium levels are in excess of what is required for normal biological function, another hormone promotes its deposition in bones to later provide the element when blood levels of it fall below normal
• Another hormone of bone tissue regulates glucose metabolism

Question 11

Marrow

Answer 11

• A soft connective tissue that is encased in the hard outer shell offered by some bones such as the bones of the hip and thigh

Question 12

Muscular System

Answer 12

• Muscles are the organs of the muscular system consisting of primarily skeletal muscles
• Help us to move and maintain our body position
• Has a significant influence on body temperature, muscular contractions can be used to increase body temperature when its cold in order to maintain homeostasis whereas shivering involves the rapid contraction of skeletal muscles which can generate heat to stave off hypothermia

Question 13

Skeletal Muscles

Answer 13

• Also referred to as voluntary muscles since they respond to our conscious control
• The body also has two types of involuntary muscle which is not under our conscious control

Question 14

Muscles

Answer 14

• Are attached to bones by tendons

Question 15

Tendons

Answer 15

• Are connective tissue that attaches muscles to bones

Question 16

Musculoskeletal System

Answer 16

• Due to the integration and interplay of the muscular and skeletal systems, some prefer to deal with them as a single, collective organ system

Question 17

Two Types of Involuntary Muscle

Answer 17

• Smooth muscle
• Cardiac muscle
• Both muscle is not under our conscious control

Question 18

Smooth Muscle

Answer 18

• Found in the walls of hollow organs such as the small and large intestines and the stomach
• Contracts in order to move along stuff in our body, things like the food that we eat being churned in our stomach and passed through our intestinal tract during the process of digestion and eventually excretion

Question 19

Cardiac Muscle

Answer 19

• Found in the heart is what makes our heart beat

- Contractions are what allows the heart to act as a pump that moves blood within the circulatory system

Question 20

Nervous System

Answer 20

• Consists of the brain, spinal cord and the nerves
• Together the brain and spinal cord make up the Central Nervous System which collectively provides the central control system of the human body
• Collectively it facilitates communication between organs, the integration of body functions, control of body functions and recognition of sensory stimuli
• It is a fast responding and fast acting control system, enabled by the activity of our nerves via nerve impulses, electrical signals that travel along nerve fibres to send information to the spinal cord and the brain

Question 21

CNS (Central Nervous System)

Answer 21

• Together the brain and spinal cord make up this system to provide the body with central control
• CNS most particularly the brain is what makes us us, and helps us recognize pain, feel of anxiety and contemplate our existence

Question 22

PNS ( Peripheral Nervous System)

Answer 22

• The cranial and spinal nerves along with their branches make up this system
• This is where it connects the central nervous system to the periphery of our bodies
• The sense organs of the PNS can recognize stimuli such as heat, light, sound and taste

Question 23

The Endocrine System

Answer 23

• Communicates with hormones excreted into the bloodstream by ductless glands
• Works with the Nervous System to provide communication and control amongst organ systems

Question 24

Neuroendocrine System

Answer 24

• Just like the muscular and skeletal systems, the Endocrine and Nervous System are lumped into a single system

Question 25

Hormones of the Endocrine System

Answer 25

• Stimulate human growth and development, reproduction, metabolism, electrolyte balance and acid-base balance
• Hormones also control the calcification and decalcification of bones in order to promote homeostasis in blood calcium levels

Question 26

Fight or Flight Response

Answer 26

• If you’ve experienced the whole-body effects of stress and anxiety, you’re quite familiar with the influence of the endocrine system as it’s an important part of the the fight or flight response that results from an awareness of the existence of some sort of threat
• The impact of your endocrine system persists until the hormones at play are metabolized and excreted

Question 27

Examples of Hormones

Answer 27

• Estradiol
• Insulin
• Testosterone
• Growth Hormone
• Epinephrine

Question 28

The Cardiovascular System

Answer 28

• Sometimes also referred to as the “Circulatory System”
• It circulates blood within the body
• It must be a closed system within which that blood can circulate
• System itself consists of the heart which pumps blood and the arteries, veins and capillaries through which that blood is pumped
• This closed loop functions to transport oxygen and nutrients to and carbon dioxide and wastes away from cells
• Serves to move heat around the body, allowing it to preserve or lose heat

Question 29

Blood

Answer 29

• Transports hormones of the Endocrine system and immune cells from the immune system
• Heart pumps about 5 quarts of blood per minute, beats about 100,000 times per day, about 35 million times per year

Question 30

Lymphatic System

Answer 30

• The lymphatic organs (lymph nodes, thymus, spleen and tonsils) and the lymphatic vessels make up this system
• Aimed at providing a defensive posture against pathogens and other undesirable things encountered in our environment
• Plays an important role in “cleaning up” dead cells and killing or isolating cancerous cells

Question 31

Lymphatic Vessels

Answer 31

• Carry a liquid called lymph which contains water, fats, and proteins and immune system cells
• Lymph does not circulate, it simply returns into general circulation via the bloodstream
• They are dead end vessels, as lymph travels from the distal ends of these vessels and is eventually dumped into blood circulation through one of two ducts
• Plays an important part in fat transport from the digestive tract and serve as a drainage system for tissues, preventing the buildup of fluid tissue spaces (when things are functioning properly)

Question 32

Lymph Nodes

Answer 32

• Nodes and other Lymphoid organs filter lymph of pathogens and other undesirables and off specialized locations for the immune system

Question 33

Phagocytes

Answer 33

• Known as “eating cells” such as macrophages along with other immune system cells and molecules can eliminate pathogens either through their envelopment and destruction or via chemical reasons that destroy the viability of the pathogens in question

Question 34

The Respiratory System

Answer 34

• Works along with the Cardiovascular System in getting oxygen to cells, and carbon dioxide away from cells
• Cardiovascular system transports those gases its the respiratory system that does the work of gas exchange
• A breath taken through the nose passes by the pharynx (the throat) and then past the larynx (voice box) through the trachea, into the bronchi and finally into the lungs, exhaling follows the opposite course to expel air from the lungs
• Lining of the respiratory tract serves to humidify the air that we breath while mucus within the tract serves to trap some potential lung irritants- things like particles of dust, or pollen preventing their interference with normal breathing
• Contributes to the regulation of pH in the body which plays a role in maintaining acid-base balance

Question 35

Lungs

Answer 35

• Bronchial Tree is made up of the ever smaller branches of the bronchi; the smallest called bronchioles- terminates in the alveoli
• Thin walled sacs like tiny bubbles, the alveoli are surrounded by capillaries which provide the interface for gas exchange via diffusion with the cardiovascular system
• The lungs fill and empty with air, in large part due to movement of the diaphragm with an assist from intercostal muscles

Question 36

The Digestive System

Answer 36

• Facilitates the ingestion of food and drink, as well as the excretion of wastes
• Has a unique morphology in the human body, its a tube that is open on each end referred to as the alimentary canal
• When you eat or drink enters the mouth, passes through the pharynx, and down the esophagus, then enters the stomach which empties into the small intestine and then the large intestine. The leftovers, treated as waste, make their way first to the rectum, before being expelled from the anal canal
• Each of the structured referred to is the primary organs of this system
• The accessory organs or secondary organs of this system include teeth, tongue, salivary glands, liver, gallbladder, pancreas, and appendix

Question 37

The Urinary System

Answer 37

• Consists of the kidneys which filter waste from the blood while contributing to the maintenance of homeostasis with respect to acid-base balance (pH), water, and electrolytes
• Wastes are cleared from the blood into urine which forms in the kidneys and is transported to the urinary bladder via the ureters. Once collected in the bladder, urine is passed through the urethra
• In the Female, the urethra passes urine and nothing else
• In the male the urethra plays double duty serving as it does to pass seminal fluid upon ejaculation in addition to its function in the urinary system

Question 38

The Reproductive Systems

Answer 38

• Propagating one’s genes so that a bit of ourselves will transcend our own generation
• Both systems have gonads which produce the sex cells and hormones that are required to fulfill this task

Question 39

Female Reproductive System

Answer 39

• The gonads are the ovaries which produce ova (eggs)
• Ova released from the surface of the ovaries travel through the uterine tubes (fallopian tubes)
• If an ovum happens to become fertilized, it implants in the wall of the uterus where is taps into the mother’s blood supply for duration
• After 9-ish months a fully formed baby is squeezed out by the muscles of the uterus through the cervix then the vagina
• Female external genitalia is not the vagina, it is referred to as the vulva. The vagina is an internal structure
• The mammary glands are considered part of the female reproductive system because of the role that they play in the production of milk to feed offspring

Question 40

Male Reproductive System

Answer 40

• The gonads are the testes which produce sperm, the male sex cells, along with the hormone testosterone
• The vas deferens (or ductus deferens) extends from the testes into the ejaculatory duct which delivers sperm to the urethra which itself passes through the prostate gland
• The prostate is an exocrine gland also called a ducted gland
• The prostate along with other accessory glands produce lubricating and nutritive fluids that help the sperm make its way through the urethra and contribute to its survival in the vaginal environment
• The external genitalia of the male is composed of the penis through which the urethra passes and the scrotum, a pouch like structure holds the testes