Chapter 16 – The Body’s Systems

16.1: Homeostasis and Osmoregulation

_______________________ refers to the relatively stable state inside the body of an animal.

Animal organs and organ systems constantly _______________ to ___________ and external changes to maintain this steady state.

Examples of internal conditions maintained by homeostatic mechanisms are:

1. _________________________________

2. _________________________________

3. _________________________________

Most homeostatic mechanisms operate by _____________________ feedback.

Two examples of factors regulated by homeostasis are _______________________ and ______________content. The processes that maintain these two factors are called _____________________________ and ___________________________________.

  1. Homeostasis
  1. The goal of homeostasis is the maintenance of equilibrium around a specific value called a  _________   _____________.
  2. A change in the internal or external environment is called a _________________.
  3. A stimulus is detected by a ______________________.
  4. The receptors sends information to a ______________  _____________ which relays signals to an effector that is able to cause an appropriate change.
  1. Thermoregulation
  1. Animals that do not have internal control of their body temperature are called ____________________________, whereas animals that maintain a   constant body temperature in the face of environmental changes are called __________________________________.
  2. List three ways that animals conserve or dissipate heat.
  1. ____________________________________________________________
  2. ____________________________________________________________
  3. ____________________________________________________________
  1. Which body system coordinates thermoregulation?
  1. Osmoregulation
  1. The process of maintaining salt and water balance is called _______________________________.
  2. Define osmotic balance –
  3. The fluid that surrounds the cells and tissues of the body is called _____________________________.
  4. A compound that dissociates into ions when dissolved into water is an ___________________.
  5. A compound that does not dissociate into ions when dissolved into water is an ____________________________________
  1. Excretory system
  1. What are the functions of the human excretory system?
  2. What are the components of the human urinary system?
  1. _____________________a pair of bean-shaped organs
  2. ____________________ carries urine from the kidneys to the urinary bladder.
  3. _______________ ________________ is the temporary storage organ for urine.
  4. _______________ carries the urine from the urinary bladder to the outside of the body.
  1. The three internal regions of the kidney are the outer __________ and the inner __________.
  2. The renal cortex contains the _______________ the functional units of the kidney that produce urine and transports it to the ______________ urine-bearing tubes that exit the kidney and join to the urinary bladder. The _____________ ________ is the part of the kidney that collects the urine from the nephrons and drains it into the ureters.
  3. Blood enters the kidneys via the ______________ artery which branches off the aorta. This blood travels through a series of smaller vessels until it comes in contact with the waste-collecting tubules of the nephrons in a structure called the _____________________.
  4. Water and many solutes leave the blood and enter the nephrons.  Useful materials are reabsorbed back into the blood whereas waste materials remain in the waste collecting tubules forming urine.
  5. Blood leaves the glomerulus and enters a series of larger and larger vessels until it exits the kidney by way of the _____________ vein.
  6. The waste product (urine) is collected into larger tubules until it reaches the renal pelvis, where it will collect into the ureters. From there the urine travels to the urinary bladder to be stored.
  7. When the bladder is full sensory nerves, stretch receptors send a signal that it needs to be emptied.  These signals create the urge to urinate. The conscious decision to urinate opens up the sphincters (rings of smooth and voluntary muscle) that close off the opening to the ___________________ that allows urine to leave the body.

16.2: Digestive System

  1. The Human Digestive System
  1. The process of digestion begins in the _________________ with the intake of food.
  2. The ______________ play an important role in masticating or physically breaking the food into smaller particles.
  3. The __________________ present in saliva chemically break down food.
  4. The swallowed food enters a long, muscular tube called the __________________.
  5. Wave-like smooth muscle contractions called ______________________ propel the food to the stomach.
  6. The contents of the stomach are extremely ______________ with a pH between _________ and ________.
  7. Further breakdown of the food occurs in the small ________________.  
  8. The waste material left after digestion is completed travel to the large _________________ where the material is compacted into feces, stored and then excreted through the ______________.
  1. Oral Cavity
  1. Both physical and chemical digestion begins in the mouth or ________  _________.
  2. The food is broken down into smaller particles by (chewing) ________________.
  3. Saliva contains mucus that moistens the food and buffers the pH of the food. Saliva contains the enzyme ________________ which has antibacterial action.  It also contains the enzyme _____________________ which begins the breakdown of complex carbohydrates (starch) into maltose (a disaccharide). Another enzyme produced by the tongue ______________ that begins the breakdown of fats or lipids.
  4. Chewing and the wetting action of saliva together with the tongue prepare the food into a mass collectively called a __________________.
  5. By swallowing the tongue pushes the bolus into the pharynx and the esophagus.  The esophagus leads to the stomach.  When swallowing a flap of tissue called the _____________________ covers the opening to the trachea and keeps the food out of the lungs.
  1. Esophagus
  1. The tubular organ that connects the mouth to the stomach is the ____________________.
  2. The smooth muscles of the esophagus under ___________________ which pushes the food towards the stomach. This movement of the smooth muscle is an ______________ reflex. It occurs in response to swallowing.
  3. Ring-like muscles called ________________________ form valves in the digestive system.
  4. The gastro-esophageal sphincter or _________________ sphincter is located at the stomach end of the esophagus.  It opens in response to swallowing and the bolus enters the stomach. When there is no swallowing this sphincter is closed.  When the contents of the stomach leak past this sphincter back into the esophagus, ___________ reflux or ___________________ occurs as a result.
  1. Stomach
  1. A large part of _____________ digestion occurs in the stomach (a sac-like organ) that secretes gastric juice
  2. Protein digestion is carried out by the enzyme called ____________. The low pH of the stomach contents is due to the secretion of hydrochloric acid (HCl) which kills many of the microorganisms in the food.
  3. The churning action of the stomach is due to the rhythmic contraction and relaxation of the smooth muscle walls of the stomach. The mixing of the partially digested food with gastric juice forms a substance called _______________.
  4. Why is the lining of the stomach not affected by the secretion of gastric juice?
  1. Small Intestine
  1. Chyme moves from the stomach to the ____________   __________________, which is the organ where digestion of protein, fats, and carbohydrates is completed. The lining of the small intestine consists of many finger-like projections called __________. The top of these finger- like structures  has many microscopic projections called ___________. These projections along with the many folds, increase the surface area of the small intestine and increase the absorption efficiency of the ______________________.
  2. The three parts of the small intestine are the _______________, the ________________, and the ______________________. The duodenum is separated from the stomach by the ____________   ______________. Here chyme is mixed with _____________________ juices that contains bicarbonate which neutralizes the acidity of the chyme.  Also, pancreatic juices contain several enzymes that breakdown ______________, _________________, ______________, and fats.
  3. _______________ is produced by the liver and is stored in the gall bladder. It enters the duodenum through the bile duct. Bile contains __________  ________, which aids in the digestion of lipids.
  4. Undigested food is sent to the___________ from the ileum. The ileum ends, and the large intestine begins at the ________________ valve. The ________________ appendix is located here and has a minor role in ____________________________.
  1. Large Intestine
  1. The ___________   _______________ reabsorbs the water  from the remaining indigestible material.
  1. Check for understanding:
  1. T or F: The larger intestine is smaller in length but larger in diameter compared to the small intestine?
  1. The three parts of the large intestine are the _____________, ____________ and the rectum. The ______________ joins the ileum to the ____________ and receives waste matter from the ileum. The colon is home to many bacteria or ______________ ________________ that aid in the digestive processes. The four regions of the colon are the ___________________ colon, _______________________ colon, the ______________________ colon, and the _____________________colon.
  1. List the main functions of the colon:
  2. The ________________ stores feces until defecation.  The ______________ is an opening at the far-end of the digestive tract and is the exit point for feces. Two sphincters regulate the exit of feces, the inner sphincter is a ring of smooth muscle and is_____________________ whereas the outer sphincter is composed of skeletal muscle and is _________________________________.
  1. The Accessory Organs
  1. The ________________ produces bile that aids in the digestion and absorption of fats.
  2. The ___________________ stores bile which has been produced by the liver.
  3. The pancreas secretes ______________ that neutralizes the acidic chyme and a variety of enzymes for digestion.
  1. Nutrition
  1. The human body can synthesize many of the molecules needed for function from  precursors, but there are some nutrients that must be obtained from food. These are the ________________  _______________ meaning they must be consumed because the body cannot produce them.
  2. ___________________, a class of essential organic molecules are required in small amounts, and many of these assist enzymes in their functioning.
  3. ______________________ are a set of essential inorganic nutrients that must be obtained from food. These perform many functions and the body cannot function without them.
  4. Certain _____________  ________________ cannot be synthesized by the body and must be obtained from food.  The human body can only synthesize only 11 out of the 20 required amino acids. These amino acids are termed the ______________ amino acids.

16.3: Circulatory and Respiratory Systems

  1. The Respiratory System
  1. During inhalation the _____________________ descends creating a negative pressure around the lungs causing them to inflate.  Air enters through the ________  __________ located inside the nose.  Here the air is warmed and humidified before it passes through to the lungs.
  2. From the nasal cavity air passes through the ______________ (throat) and the _____________ (voice box) into the ______________ (wind pipe).
  3. The end of the trachea divides into two ____________ that enter the left and right lung. Air enters the lungs through the _________________ bronchi, which divides into smaller and smaller diameter _____________ until the passageways are less than 1 mm in diameter when they are called ____________________. The final bronchioles are the ___________________________ bronchioles. Attached to the end of each respiratory bronchiole are the __________________ ducts. At the end of each duct are alveolar sacs, each containing 20 – 30 _______________.  Gas exchange only occurs in these.
  1. The Circulatory System
  1. Explain the difference between an open and a closed circulatory system.
  2. The Heart
  1. The heart consists two pumps: one that pumps blood to the lungs and back to the heart ________________________________, and the other __________________________________________that pumps blood to the rest of the body tissues and the heart itself.
  2. The left side of the heart is larger than the right side which correlates with the different sizes of the two pumping circuits. The human heart consists of four chambers two ___________ and two ____________________. There is one atrium and one ventricle on each side of the heart. The right atrium receives deoxygenated blood from the major veins the _______________________ drains blood from the head and from the arms, the ______________________ drains blood from the lower organs and the legs. This deoxygenated blood passes from the right atrium through the __________________ valve (which prevents backflow of blood) into the right _________________. The blood is then pumped  to the lungs for oxygenation. The left atrium receives the oxygen-rich blood from the lungs, this blood passes through the ___________ valve to the left ventricle. From here the blood is pumped into the _______________ the major artery of the body, taking oxygenated blood to the organs and muscles of the rest of the body. This pattern of pumping blood in the human body is referred to as _________________  ___________________ and is found in all mammals.
  1. The Cardiac Cycle
  1. What is the main purpose of the heart?
  2. The _______________  ______________ is the flow of blood through the heart coordinated by electrochemical signals that cause the heart to contract and relax. The contracting phase of the cardiac cycle is  called ________________, whereas the relaxation phase is called _________________.  The signal for contraction begins at a location outside of the right atrium (SA Node). It moves across the atria causing them to contract and force blood through the valves into the ventricles.  The signal reaches a point between the right and left ventricle (AV Node) which causes the walls of the ventricles to contract.  On the right side of the heart, the blood is pushed through the pulmonary valve into the pulmonary arteries, and on the left side through the aortic valve into the aorta. The closing of the tricuspid and bicuspid valves causes the “lup” sound whereas the closing of the aortic and pulmonary valves during ventricular relaxation produces the “dup” sound of the heartbeat when heard through a stethoscope.
  3. The electrical impulses of the heart can be observed as an _________________________________ (ECG) a record of the of the electrical impulses of the heart muscle.
  1. Blood Vessels
  1. __________ take blood away from the heart.  The main artery of systemic circulation is the ___________ which branches into major arteries that take blood to different parts of the body. The arteries near the heart have heavy, but elastic walls that even out the pressure differences caused by the beating heart. The arteries further away from the heart have more smooth muscle in their walls that can constrict or relax to affect flow rates of blood.  The major arteries split into smaller arteries, and finally, ______________ which eventually take blood to the capillary beds.
  2. The capillary beds contain a large number, 10’s to 100’s of ___________________. These capillaries are narrow-diameter tubes that can fit single red blood cells and function in the exchange of nutrients, wastes, and gases between the blood and the tissues. Capillaries converge into _____________ that connect to minor veins that finally connect into larger veins and eventually into major veins.  Blood vessels that return blood to the heart are called ________________. Since pressure is lower in veins than in arteries, they have valves along their length to prevent backflow of blood away from the heart. Using Figure 16.12 on page 420 name five of the major arteries and five major veins of the body.
Five Major ArteriesFive Major Veins

16.4 Endocrine System

  1. The __________________ system produces hormones that function to control and regulate different body processes. Hormones stimulate a response by binding to ____________ found on the surface of cells. Many hormones are secreted in response to signals from the nervous system.
  2. The chemical signals produced by endocrine glands are released into the blood or other body fluids are called ___________________________.  The cells that secrete hormones are located in specific organs called ____________________ glands. Cells, tissues and organs that secrete hormones make up the ____________________ system.
  1. One example of an endocrine organ is the ___________________________ which produces the hormones insulin and glucagon to regulate blood sugar.
  1. ____________________ glands differ from endocrine glands because they secrete chemicals through ducts that lead outside the gland (not to the blood). One example is the ___________  ________________ that carry sweat through ducts to the surface of the skin. Which body organ has both endocrine and exocrine functions? Name the organ and describe its functions below (see page 421).
  2. How Hormones Work
  1. Hormones cause changes in target cells by binding to specific cell-surface or _________________________    ________________________ receptors. Hormones circulate through the body but only affect those cells that have those receptors that are specific to that hormone. A cell may have many receptors for the same hormone or multiple receptors for different types of hormones.
  2. The number of receptors available to respond to a hormone can change over time resulting in decreased or increased cell sensitivity to that hormone.  In _______ regulation the number of receptors increases in response to rising hormone levels. When the number of receptors decreases in response to increased hormonal levels, _________________ regulation results in reduced cellular activity.
  1. Endocrine Glands
  1. The ____________________ gland is located at the base of the brain.  It is attached to the ___________________.  It is composed of two lobes, anterior and posterior.  The posterior lobe stores and releases _____________________ and _________________________ (ADH). The _________________________ lobe responds to hormones produced by the hypothalamus by producing its own hormones, many of which regulate the functioning of other endocrine organs and glands.
  2. The six hormones produced by the anterior pituitary and their functions fill in the table on the next page. Use the table located on page 424 for assistance
Anterior Pituitary HormonesFunctions of Each One
2.Stimulates milk production
  1. The _______________________  _______________ is located in the neck.  It consists of follicle cells that synthesize the thyroid hormones _____________ (T4) which contains four iodine atoms and triiodothyronine known as ________ because it contains three iodine atoms. These hormones are released by the thyroid in response to thyroid-stimulating hormone (TSH) released by the anterior pituitary. Another hormone released by the thyroid gland is _________________ which works to reduce blood calcium levels.
  2. On the posterior surface of the thyroid gland are 2 to 6 ______________________  _____________________ (most people have four).  These glands produce _______________________ (PTH) which functions in raising blood calcium levels.
  3. The ___________________ is located between the stomach and the proximal portion of the small intestine. It contains ______________ cells that produce and release digestive enzymes and ___________________ cells that release the hormones insulin and glucagon.
  4. The endocrine cells of the pancreas form clusters called ______________________  _____________ or islets of Langerhans. Here are two types of cells, alpha cells produce _________________ and _______________cells that produce insulin.  _______________ causes the release of glucose to the blood from the liver and ______________________ facilitates the uptake of glucose by the ____________________ cells.
  5. Located on top of the kidney’s are the _______________ glands.  Each adrenal gland consists of an outer _________________ with an inner _______________.  Each region secretes different hormones. The adrenal cortex secretes mineralocorticoids, glucorticoids, and androgens. The main mineralocorticoid which regulates ion concentrations in body fluids is ______________________. The release of this hormone is stimulated by a decrease in blood pressure, blood volume or blood concentrations of sodium ions, or by an increased in blood potassium levels. The glucorticoids (cortisol, corticosterone and cortisone) maintain proper blood-glucose levels between meals and control a response to stress by increasing glucose synthesis from non-carbohydrate sources and interact with epinephrine to cause vasoconstriction (a raise in blood pressure).
  6. The _____________, the male testes and female ovaries produce _____________ hormones. The testes produce androgens, ___________________ is the most prominent which allow for the development of male secondary sex characteristics and sperm production. The ovaries produce ________________________ and _________________________ which cause secondary sex characteristics in females, regulate egg production, control pregnancy and prepare the body for childbirth.
  7. Several other non-endocrine organs possess endocrine cells. The atrial walls of the heart release a hormone that causes a __________________ in blood volume and blood ________________________ and reduces blood Na+ levels.
  8. The kidneys possess endocrine function. In response to low oxygen levels ____________________________ (EPO) is released.
  1. Regulation of Hormone Production
  1. Hormone production and release is primarily controlled by ____________________ feedback mechanisms.

16.5: Musculoskeletal System

  1. Skeletal System
  2. List the five main functions of the human skeleton
  1. ____________________________________________________________________
  2. ____________________________________________________________________
  3. ____________________________________________________________________
  4. ____________________________________________________________________
  5. ____________________________________________________________________
  1. The ______________  ___________________ forms the central axis of the body.  List the function for each component listed for the axial skeleton
  1. Skull -
  2. Auditory ossicles –
  3. Hyoid bone –
  4. Vertebral column –
  5. Thoracic cage –
  1. The _____________________   _______________________ is composed of the bones of the upper and lower limbs.  It also includes the pectoral and pelvic gridles which attach the upper and lower limbs to the body. List the functions for the following components of the appendicular skeleton.
  1. Pectoral girdle (also name the bones that make up this component) –
  2. Pelvic girdle (also name the bones that make up this component) –
  1. Joints and Skeletal Movement
  1. The point at which two or more bones meet is called a ________________.
  2. Joints are classified on the basis of _________________ or ____________________
  1. The structural classification divides joints into ________________, __________________, and ________________________ joints based on the material composing the joint and the presence or absence of a joint cavity.
  1. The bones of ________________ joints are held together by fibrous connective tissue, which results in little or no movement. Examples of this type of joint include:
  1. _______________________________________
  2. _______________________________________
  1. ________________________________ joints are joints in which the bones are connected by cartilage. These joints allow minimal movement.  An example is the _____________ of the backbone.
  2. ______________________  ______________ are the only joints that have a space between the adjoining bones called the joint cavity and is filled with fluid that lubricates the joint, reducing friction between the bones. The ends of the bone are covered with cartilage and the entire joint is surrounded by a capsule.  These joints possess the greatest movement of all joint types. ___________________, _______________, and _________________ are examples of this type of joint.
  1. Muscles
  1. ________________  __________________ ________________ forms skeletal muscles which attach to bones, and skin and control locomotion and any other voluntary movement. What kind of appearance does this type of muscle have under the microscope?
  2. __________________  ______________________ ______________ makes up the walls of hollow organs such as the intestines, stomach, respiratory tract and blood vessels.  How does smooth muscle differ from skeletal muscle?
  3. ___________________   _________________  ________________ is only found in the heart.  How is cardiac muscle similar to and different from skeletal muscle and smooth muscle?
  4. Skeletal muscle cells are called ________________.  Within each fiber are ______________ which lie parallel to the length of the fiber. The plasma membrane of the skeletal muscle fibers is called the __________________________. The muscle fiber contracts when the myofibrils shorten.  The cytoplasm of the muscle fiber is called the ___________________. The striated appearance of skeletal muscle tissue is a result of repeating bands of the proteins ____________ and ___________ along the length of myofibrils. Myofibrils are composed of ______________________ which are two main types  thick and thin filaments. Thick filaments are composed of the protein __________ while ________ filaments are composed of actin. The thick and thin filaments alternate with each other in a structure called a ______________________________ which is the unit of contraction for the muscle fiber. Muscle contraction is stimulated by ______________________ signal from a nerve cell associated with the muscle fiber. The source of energy for muscle contraction is _____________.

16.6: Nervous System

  1. Neurons and Glial Cells
  1. Cellular components of neurons
  1. Cell body or __________ that contains the metabolic machinery.
  2. _________________ are tree-like that extend away from the soma to receive messages from other neurons at specialized junctions called ______________________.
  3. The plasma membrane of a neuron is impermeable to ions. For ions to enter or leave they must pass through ___________ ____________________ that span the membrane. Ion channels that change their structure in response to voltage changes are called __________________ - ____________ ion channels.
  4. A neuron at rest is negatively charged at approximately  – 70 millivolts (mV). This voltage is called the _______________  _________________ potential. This is caused by differences in ion concentrations inside and outside of the cell, and the selective permeability created by ion channels.  The sodium – potassium pumps in the cell membrane produce the different ion concentrations inside and outside the cell by bringing in 2 ____ ions for every three ___________ removed. One molecule of __________ is needed for each turn.
  5. When a neurotransmitter molecule binds to receptors in the dendrite cell plasma membrane ion channels open and allow sodium ions to enter the neuron this results in ___________________ of the membrane a decrease in the voltage across the neurons cell membrane.  If the signal is strong enough to reach the axon (threshold of excitation)  depolarization will create a positive feedback loop as more Na+ ions enter the cell resulting in a self-propagating reversal of the resting membrane potential called an _____________  ________________________.
  6. An _____________ is a tube-like structure that propagates the signal from the cell body to specialized endings called __________  ________________.
  7. Some axons are covered by a _____________  ________________ which acts as an insulator.
  1. How Neurons Communicate
  1. The gap between an axon of one neuron and the dendrites or cell body of another neuron is called the ______________ cleft.
  1. The Central Nervous System (CNS)
  1. The central nervous system is made up of the _____________ and ____________ ______________. The three layers of protective covering are called ____________. The outermost layer is the ___________ mater, the middle layer is the ______________________ mater and the inner layer, the _________ mater directly contacts and covers the brain and spinal cord.  The space between the arachnoid and pia maters is filled with ________________________________ (CSF) which acts as a cushion and shock absorber.
  1. The Brain
  1. The ________________ the part of the central nervous system contained in the cranial cavity of the skull. It is composed of the following components, the
  1. _____________  ___________________
  2. _____________  ___________________
  3. _____________  ___________________
  4. ________________________________
  5. ________________________________
  6. ________________________________
  7. ________________________________
  8. ________________________________
  1. A thick fiber bundle of tissue called the _______________  __________________ connects the two hemispheres of the brain. Which parts of the brain make up the cerebral hemispheres?
  1. _____________________________________
  2. _____________________________________
  3. ______________________________________
  1. Each cerebral hemisphere contains regions called _____________ which are involved in different functions. The ___________ lobe is at the front of the brain and also contains the motor cortex.  The _____________ lobe is at the top of the brain and contains neurons involved in speech and reading. This lobe also processes somatosensation – pressure, pain, heat, cold, and proprioception – the sensing of how parts of the body are positioned in space. The ___________ lobe is at the back of the brain and is primary involved in the sense of _____________.  The ______________ lobe is involved in processing and interpreting sounds.  It also contains the _______________________ which processes memory formation.  The interconnected brain areas called ____________  ______________ play important roles in movement control, posture and motivation.  
  2. The ____________ acts as a gateway to and from the cerebral cortex.  It receives both sensory and motor inputs.  It helps to regulate consciousness, arousal, and sleep states.
  3. The ____________________ controls the endocrine system by regulating the pituitary gland.  The hypothalamus controls body temperature and regulates circadian rhythms.
  4. The _____________  _______________ regulates emotions as well as behaviors related to fear and motivation. The temporal lobe structure called the ________________ which is important for the sensation of fear and recognizing fearful faces.
  5. The _____________ sits at the base of the brain at the top of the brainstem.  It aids in the coordination of movement and learning new motor tasks.
  6. The _______________ connects the brain  with the spinal cord, and regulates the most important functions of the nervous system including breathing, swallowing, _____________________, ____________________, _____________________ and information integration.
  1.   Spinal cord
  1. The spinal cord connects the brain with the peripheral nervous system and controls motor reflexes.
  1. Peripheral Nervous System (PNS)
  1. The peripheral nervous system can be broken down into the _________________ nervous system which controls body functions and the ____________ - _______________________________ which transmits sensory information to the CNS and sends motor commands from the CNS to the muscles.
  2. The autonomic nervous system is the relay between the CNS and the internal organs, smooth muscle, and all exocrine and endocrine glands.
  1. The ____________________________________________ is responsible an animal makes when it encounters a dangerous situation. It is activated in stressful situations. Its functions include an accelerated heart rate and inhibited digestion.
  2. The ____________________________________________________ resets organ functions after the sympathetic nervous system is activated. It is responsible for lowering blood pressure, reducing heart rate and stimulation of digestion.
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