BSF final exam

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Questions and Answers

What is the primary stimulus for initiating breathing?

Low oxygen levels

Low blood pH

High atmospheric pressure

High CO2 levels (correct)

Which muscle is primarily responsible for inhalation?

Diaphragm (correct)

Abdominal muscles

Internal intercostal muscles

Pectoral muscles

What happens to intrapleural pressure during inhalation?

It becomes less negative

It becomes more negative (correct)

It remains constant

It increases

How does exhalation occur?

By relaxing the diaphragm and external intercostal muscles Signup and view all the answers

What is the primary mechanism for gas exchange in the alveoli?

Diffusion across the alveolar wall Signup and view all the answers

What is the function of hemoglobin in red blood cells?

To transport oxygen throughout the body Signup and view all the answers

Which respiratory muscle helps expand the chest cavity from side to side?

External intercostal muscles Signup and view all the answers

What role does the serous fluid play in the respiratory system?

It creates adhesion between pleural membranes Signup and view all the answers

What is the primary function of the alveoli in the lungs?

Exchange of oxygen and carbon dioxide Signup and view all the answers

Which structure primarily separates the nasopharynx from the oral cavity during swallowing?

Soft palate Signup and view all the answers

What drives the mechanism of ventilation in the lungs?

Contraction of the diaphragm and intercostal muscles Signup and view all the answers

Which part of the respiratory system is responsible for conducting air but not involved in gas exchange?

Bronchioles Signup and view all the answers

What is the primary role of the respiratory muscles?

Change the volume of the thoracic cavity Signup and view all the answers

During gas exchange, where does oxygen move from and to?

From alveoli to blood Signup and view all the answers

Which statement is true regarding the bronchioles in the respiratory system?

They primarily function as air passages. Signup and view all the answers

How does the pulmonary blood circulation differ from systemic circulation?

It transports deoxygenated blood to the lungs. Signup and view all the answers

What is the primary function of the larynx?

Speaking and air passage Signup and view all the answers

What is the purpose of the C-shaped cartilage in the trachea?

To prevent collapse and maintain openness Signup and view all the answers

Where does gas exchange primarily occur in the lungs?

Alveoli Signup and view all the answers

What component is important for effective gas diffusion in the alveoli?

Capillary network Signup and view all the answers

What is ventilation in the context of respiratory processes?

The movement of air to and from the alveoli Signup and view all the answers

Which part of the brain is primarily responsible for generating impulses for breathing?

Medulla Signup and view all the answers

What structure ensures that the esophagus can expand during swallowing?

Posterior gaps in the trachea Signup and view all the answers

What is the role of pulmonary surfactant in the alveoli?

Mix with tissue fluid to reduce surface tension Signup and view all the answers

What is the primary function of dendrites in a neuron?

Transmit impulses toward the cell body Signup and view all the answers

What role do Schwann cells play in nerve tissue?

They form the myelin sheath around axons Signup and view all the answers

Which type of neuron is responsible for transmitting impulses from receptors to the central nervous system?

Sensory neuron Signup and view all the answers

What is the function of cholinesterase in relation to neurotransmitters?

It inactivates neurotransmitters to prevent continuous impulses Signup and view all the answers

Which of the following describes the nature of spinal cord reflexes?

They function independently of the brain's direct involvement Signup and view all the answers

What is the primary role of the axon in a neuron?

To transmit impulses away from the cell body Signup and view all the answers

What is contained within the central canal of the spinal cord?

Cerebrospinal fluid Signup and view all the answers

What is the primary function of the lower esophageal sphincter?

To regulate the entry and backup of stomach contents Signup and view all the answers

Which layer of the alimentary tube is primarily responsible for lubricating the passage of food?

Mucosa Signup and view all the answers

What role does Auerbach's plexus serve in the digestive system?

Increases peristalsis Signup and view all the answers

Which structure is responsible for digesting food gradually in the stomach?

External Muscle Layer Signup and view all the answers

Which section of the small intestine is approximately 10 inches long?

Duodenum Signup and view all the answers

What is the role of the muscular wall of the oropharynx and laryngopharynx during swallowing?

To contract and facilitate the swallowing reflex Signup and view all the answers

Which characteristic distinguishes the trachea from other respiratory structures?

The presence of 16-20 C shaped cartilage pieces Signup and view all the answers

Which of the following features is correctly associated with the lungs?

Elastic connective tissue aids in exhalation Signup and view all the answers

How is the structure of the larynx significant in its function?

It houses the vocal cords that are essential for sound production Signup and view all the answers

What is the significance of the capillary network surrounding the alveoli?

It allows for efficient diffusion of gases, enhancing gas exchange Signup and view all the answers

What is the primary function of the choroid plexus in the central nervous system?

Producing cerebrospinal fluid Signup and view all the answers

Which of the following statements about blood types is true regarding type O blood?

It is considered the universal donor due to the absence of A and B antigens Signup and view all the answers

Why is the epiglottis an important structure in the respiratory system?

It prevents food from entering the trachea during swallowing Signup and view all the answers

What occurs when an Rh-negative individual receives Rh-positive blood?

Antibody production may occur gradually Signup and view all the answers

What differentiates the primary bronchi from smaller bronchi?

Their length and diameter are significantly larger Signup and view all the answers

Which layer of epithelial tissue primarily lines the trachea?

Ciliated epithelium with goblet cells Signup and view all the answers

Which layer of the meninges is characterized as the outermost and the thickest?

Dura mater Signup and view all the answers

What is the role of atrial natriuretic hormone (ANH) in the cardiovascular system?

Reduces blood volume by promoting sodium and water excretion Signup and view all the answers

What is the relationship between pleural membranes and serous fluid?

Serous fluid prevents friction and keeps membranes together Signup and view all the answers

What is the main function of the respiratory centers located in the medulla and pons?

To generate impulses for the respiratory muscles during breathing Signup and view all the answers

What is contained within the subarachnoid space?

Cerebrospinal fluid Signup and view all the answers

Which of the following best describes the cardiac muscle layer of the heart?

It is called the myocardium and provides the contractile force Signup and view all the answers

Which component is involved in the reabsorption of cerebrospinal fluid into the bloodstream?

Arachnoid villi Signup and view all the answers

What is the role of the pulmonary veins in the circulatory system?

Carries oxygenated blood from the lungs to the left atrium Signup and view all the answers

Which mechanism aids in maintaining systemic blood pressure through venous return?

Constriction of veins Signup and view all the answers

What is a primary function of the liver in relation to detoxification?

Transforming glucose to glycogen for storage Signup and view all the answers

What is the function of capillaries within the pulmonary circulation?

Facilitating gas exchange between blood and alveoli Signup and view all the answers

Which structure is responsible for the pressure changes necessary for inhalation?

Diaphragm Signup and view all the answers

What primarily initiates the exchange of gases in the alveoli?

Partial pressure differences of oxygen and carbon dioxide Signup and view all the answers

Which of the following correctly describes a characteristic of the systemic circulation?

Involves the aorta and its branches delivering oxygen-rich blood Signup and view all the answers

Which aspect of blood flow regulation is influenced by the kidneys?

Renin-angiotensin mechanism Signup and view all the answers

What occurs in the capillary networks throughout the body during systemic circulation?

Oxygen delivery to tissues Signup and view all the answers

What is the role of the left ventricle's thicker walls compared to the right ventricle?

To provide a stronger contraction for systemic circulation Signup and view all the answers

What are the consequences of a significant obstruction in the coronary vessels?

Ischemia leading to tissue infarct if unresolved Signup and view all the answers

What is the function of heart valves, especially in veins?

To prevent backflow of blood Signup and view all the answers

How is cardiac output calculated?

Stroke volume x heart rate Signup and view all the answers

What is NOT one of the five essential parts of a reflex arc?

Thalamus Signup and view all the answers

Which function is primarily associated with the hypothalamus?

Regulating body temperature Signup and view all the answers

Which part of the brain is responsible for integrating impulses before they reach the cerebrum?

Thalamus Signup and view all the answers

Which structure is considered part of the central nervous system that extends from the spinal cord to the pons?

Medulla Signup and view all the answers

What is a primary function of the cerebellum?

Coordinating movement and balance Signup and view all the answers

What function does the lower esophageal sphincter serve in the digestive system?

It relaxes to allow food to enter the stomach and contracts to prevent backup. Signup and view all the answers

Which of the following statements accurately describes the structure and function of the mucosa in the alimentary tube?

It secretes mucus for lubrication and digestive enzymes for food breakdown. Signup and view all the answers

Which characteristic of the small intestine is primarily responsible for increasing its absorptive surface area?

The microvilli on the mucosal cells. Signup and view all the answers

What is the role of the submucosa in the alimentary tube?

It contains nervous tissue that regulates the muscular layers. Signup and view all the answers

What is the primary function of the serosa in the alimentary canal?

To prevent friction between abdominal organs. Signup and view all the answers

Which statement best describes the role of iron in hemoglobin?

It enables hemoglobin to bond with oxygen for transport. Signup and view all the answers

What physiological change occurs during inhalation involving intrapulmonic pressure?

Intrapulmonic pressure falls below atmospheric pressure. Signup and view all the answers

During gas exchange in the alveoli, what drives the process of diffusion?

The pressure gradients of oxygen and carbon dioxide. Signup and view all the answers

Which type of digestion is primarily facilitated by enzymes in the digestive system?

Chemical digestion Signup and view all the answers

What is the function of the residual air in the lungs?

It prevents lung collapse by maintaining a constant volume. Signup and view all the answers

Which component of the reflex arc is primarily responsible for generating impulses in response to a detected change?

Receptors Signup and view all the answers

What is the main function of the thalamus within the central nervous system?

Integration of sensory information Signup and view all the answers

Which brain structure is responsible for regulating autonomic functions such as cardiac activity and blood vessel regulation?

Hypothalamus Signup and view all the answers

Which brain part contributes to muscle tone regulation and maintaining posture, functioning below the level of consciousness?

Cerebellum Signup and view all the answers

In what way does the medulla oblongata function to support respiratory processes?

Controlling the rhythm of breathing Signup and view all the answers

What is the primary function of the basal ganglia within the cerebral hemispheres?

Regulation of voluntary muscle movement and coordination Signup and view all the answers

Which area of the brain is specifically responsible for controlling movements involved in speech?

Broca’s motor speech area Signup and view all the answers

What is the significance of the corpus callosum in brain function?

It connects the left and right cerebral hemispheres for communication Signup and view all the answers

Which area of the brain is primarily responsible for processing general sensory information from the skin?

General sensory areas in the parietal lobes Signup and view all the answers

Which function is most closely associated with the hippocampus?

Managing memory and learning Signup and view all the answers

What is the main function of interneurons in the central nervous system?

Facilitate communication between sensory and motor neurons Signup and view all the answers

Which structure is primarily responsible for regulating breathing rhythms in conjunction with the medulla?

Pons Signup and view all the answers

What role does cholinesterase play in neurotransmission?

Inactivates neurotransmitters to prevent continuous impulses Signup and view all the answers

Which type of neuron is responsible for carrying impulses from the central nervous system to effectors?

Motor neurons Signup and view all the answers

Which part of the spinal cord is responsible for carrying sensory impulses to the brain?

Ascending tracts Signup and view all the answers

Which structure is primarily responsible for regulating muscle tone and coordinating accessory movements?

Basal Ganglia Signup and view all the answers

What is the primary role of the choroid plexus within the central nervous system?

To produce cerebrospinal fluid from blood plasma Signup and view all the answers

Which blood type can be considered the universal recipient, allowing for safe transfusion from any blood type?

Type AB Signup and view all the answers

What happens to red blood cells when an Rh-negative individual receives Rh-positive blood for the second time?

They produce antibodies leading to hemolysis Signup and view all the answers

Which layer of the meninges is characterized as the innermost and directly covers the brain and spinal cord?

Pia mater Signup and view all the answers

Study Notes

Nerve Tissue

Nerve cells are neurons, or nerve fibers
Neurons are made of cell bodies, dendrites, and axons
Cell bodies contain the nucleus
Neurons are found in the central nervous system (CNS) or near it in the body's trunk
Dendrites transmit impulses towards the cell body
Axons transmit impulses away from the cell body

Types of Neurons

Sensory neurons (afferent neurons) carry impulses from receptors to the CNS
Motor neurons (efferent neurons) carry impulses from the CNS to effectors
Interneurons are nerve cells entirely within the CNS; they are involved in thinking, learning, and memory

Nerve Tissue (continued)

Axons and dendrites are wrapped in Schwann cells to form the myelin sheath
The myelin sheath electrically insulates neurons from each other

Synapses

Neurotransmitters diffuse across the synapse and bind to receptor sites on the postsynaptic neuron's membrane
This process is carried by the next neuron's axon to the next synapse, and so on
A chemical inactivator quickly deactivates the neurotransmitter in the postsynaptic neuron's cell body or dendrites, preventing unwanted continuous impulses
Neurotransmitter is acetylcholine (in the CNS and many parts of the PNS)
Cholinesterase inactivates acetylcholine

Spinal Cord

Transmission of impulses to and from the brain
Integrating center for spinal cord reflexes
Enclosed within the vertebral canal for protection from injury
The meninges offer further protection
Extends from the foramen magnum of the occipital bone to the disc between the first and second lumbar vertebrae
Ascending tracts carry sensory impulses to the brain
Descending tracts carry motor impulses away from the brain
Central canal contains cerebrospinal fluid (CSF) which is continuous with the ventricles (brain cavities)

Spinal Cord Reflexes

Involuntary responses to stimuli
Automatic actions triggered by specific changes
Reflexes are typically independent of the brain, although the brain can influence them either by inhibiting or enhancing the reflex

Reflex Arc

Pathway of nerve impulses in response to a reflex:
Receptors detect a change and generate impulses
Sensory neurons transmit impulses from receptors to the CNS
CNS contains one or more synapses
Motor neurons transmit impulses from the CNS to the effector
Effector carries out a characteristic action

The Brain - Medulla

Connects to the spinal cord
Anterior to the cerebellum
Contains centers for cardiac activity, blood pressure, respiration, coughing, sneezing, swallowing, and vomiting

The Brain - Pons

Bulges from the upper part of the medulla
Contains two respiratory centers working with those in the medulla to regulate breathing rhythms
Acts as a bridge to connect medulla to other parts of the brain

The Brain - Thalamus

Located superior to the hypothalamus and inferior to the cerebrum
Integrates sensory impulses, making them readily interpretable to the cerebrum

The Brain - Cerebellum

Separated from the medulla and pons by the fourth ventricle
Located inferior to the occipital lobes of the cerebrum
Concerned with movement, posture, and balance; also involved in coordination and muscle tone

The Brain - Hypothalamus

Located superior to the pituitary gland and inferior to the thalamus
Function: regulation of body temperature, food intake, autonomic nervous system activity like heart rate, blood pressure, and bowel function; emotional expression, body rhythms (e.g., sleep cycles, hormone secretion).
Production of antidiuretic hormone (ADH) and oxytocin
Production of hormones that control the secretion of other hormones (releasing hormones) by the anterior pituitary gland

The Brain - Cerebrum

Largest part of the brain
Two hemispheres separated by the longitudinal fissure
Connected by the corpus callosum (200 million neurons)
Lateral ventricle within each hemisphere

Frontal Lobes

Motor areas generate impulses for voluntary movements, with a larger portion for precise hand and face movements
Left motor area controls the right side of the body, right motor area the left side of the body
Premotor areas control learned motor skills (e.g., shoe tying)
Broca's motor speech area controls mouth movements needed for speech

Parietal Lobes

General sensory areas receive and interpret impulses from skin receptors for cutaneous sensations
Left area controls the right side of the body and vice versa
Contains the areas that receive sensory impulses and interpret conscious muscle sense from stretch receptors

Temporal Lobes

Olfactory area receives impulses from nasal cavities for the sense of smell
Auditory areas receive impulses from receptors in the inner ears for hearing
Includes speech areas involved in thought preceding speech

Occipital Lobes

Impulses from the retina (in the eye) travel to the visual areas in the occipital lobes
Involved in spatial relationships, judging distance, and seeing in 3D

Association Areas

Responsible for personality, sense of humor, reasoning, and logic
Include areas responsible for learning and memory; the hippocampus is responsible for memory

Basal Ganglia

Paired masses of gray matter in the white matter of the cerebral hemispheres
Involved in subconscious aspects of movement, working with the cerebellum
Regulate muscle tone and coordinate accessory movements (e.g., swinging arms while walking)

Corpus Callosum

Band of nerve fibers connecting the left and right cerebral hemispheres
Allows communication between the hemispheres

Meninges and Cerebrospinal Fluid

Connective tissue membranes covering the brain and spinal cord
Dura mater is the thick outermost layer lining the skull and vertebral canal
Arachnoid membrane is the middle layer made of web-like connective tissue fibers
Pia mater is the thin innermost layer covering the surface of the spinal cord and brain
Subarachnoid space between the arachnoid and pia mater contains CSF

Choroid Plexus

Capillary network forming CSF from blood plasma
CSF circulates throughout the CNS
Arachnoid villi reabsorb CSF into cranial venous sinuses, returning it to blood plasma

Blood Types

ABO grouping: people with type A blood have the A antigen on their blood cells. They also have antibodies to B antigens.
People with type B blood have the B antigen on their blood cells and antibodies to A antigens.
People with type AB blood have both the A and B antigens and no blood type antibodies.
People with type O blood have neither A nor B antigens and have antibodies for both A and B antigens
Wrong blood type transfusion causes clumping and rupture of the blood cells, creating kidney damage and renal failure
The universal donor is type O. The universal recipient is type AB

RH Factor

Rh positive have the Rh antigen present. Rh negative do not have the Rh antigen.
If Rh-negative blood receives Rh-positive blood, antibodies are produced.
A first transfusion often doesn't cause problems, but a second transfusion will produce a serious transfusion reaction, with hemolysis (red blood cell destruction) and potential kidney damage.

Mediastinum and Pericardial Membranes

Mediastinum is the central part of the thoracic cavity containing the heart, great vessels, and esophagus
Pericardium, surrounding the heart, is composed of two layers: fibrous pericardium and the serous pericardium (parietal & visceral)

Chambers-Vessels and Valves

The heart is a four-chambered pump made of cardiac muscle (myocardium), lined with the endocardium (smooth for clotting prevention)
Atria (upper chambers) and ventricles (lower chambers) are separated by interatrial and interventricular septa

Heart Pathway

Blood pathway through the heart: Inferior/Superior vena cava -> Right atrium ->Tricuspid Valve Right ventricle ->Pulmonary Semilunar valve ->Pulmonary artery -> Lungs -> Pulmonary veins -> Left atrium ->Bicuspid valve ->Left ventricle ->Aortic semilunar valve ->Aorta -> Body

Atrial Natriuretic Hormone (ANH)

Atria release ANH when stretched by increased blood volume or pressure
ANH decreases sodium reabsorption in the kidneys
Water follows sodium, thereby decreasing blood volume and blood pressure

Left Ventricle

Thicker walls providing more forceful contraction
Blood flows through the aortic semilunar valve to the body (aorta). The valve also possesses chordae tendineae and papillary muscles

Coronary Vessels-Vessels around the heart that supply the heart with nutrient

Branch from the ascending aorta
Branch to smaller arteries, arterioles, and capillaries feeding the myocardium
Coronary veins collect blood from capillaries and deliver to the coronary sinus
Coronary sinus returns blood to the right atrium
If obstruction occurs, ischemia is the result (decreased oxygen supply).
If blood flow is not restored, it will become infarct (dead tissue)

Cardiac Cycle

Sequence of events during one heartbeat
Simultaneous contraction of the two atria, followed by simultaneous contraction of the two ventricles
Systole is contraction
Diastole is relaxation

Cardiac Conduction

Mechanical events regulated by the electrical activity of the myocardium
Heart cells have the ability to contract spontaneously
Sinoatrial (SA) node->atrioventricular (AV) node->Atrial myocardium->bundle of His->bundle branches->Purkinje fibers initiate and deliver electrical impulses, generating the heartbeat

Arrhythmias

Irregular heartbeats, ranging from harmless to life-threatening
Palpitations are irregular heartbeats that occur from time to time
Fibrillation is rapid and uncoordinated ventricular beat which is ineffective at pumping blood
Quivering ventricles=No pulse

Heart Rate

Normal resting pulse rate (SA node) is 60-80 beats per minute
<60 beats per minute is bradycardia
100 beats per minute is tachycardia
Well-conditioned people typically have slower heart rates

Cardiac Output

The amount of blood pumped by a ventricle in one minute
Stroke volume is the amount of blood pumped per contraction (60-80 ml)
Cardiac output = Stroke volume x Pulse rate
Starling's Law of the Heart relates cardiac output to venous return
Starling Law-The more the cardiac muscle fibers are stretched, the more forcefully they contract
Venous Return-The amount of blood returned to the heart
Ejection Fraction: Percentage of blood pumped from the left ventricle per heartbeat

Arteries

Carry blood from the heart to capillaries
Small arteries are arterioles
Composed of three layers: Tunica intima, Tunica media (thick), Tunica externa
Tunica intima-Innermost layer; smooth to prevent abnormal clotting
Tunica media- Middle layer;strong but elastic to allow arteries to constrict/dilate; maintenance of bp
Tunica external-Strong layer to prevent bursting; maintenance of bp
Volume is greater in the arteries

Veins

Carry blood from capillaries to the heart
Small veins are venules
Composed of three layers: Tunica intima, Tunica media (thin), Tunica externa
Inner layer Contains valves to prevent backflow; more in legs due to flow against gravity to get back to heart
Middle and out layer is thin because blood pressure is low in veins

Anastomoses

Connections between vessels (arteries to arteries or veins to veins)
Provide alternate pathways for blood flow if a vessel is obstructed
Arterial anastomoses, Venous anastomoses
Arterial-blood gets to capillaries of organ and removal of waste products
Venous-blood gets back to the heart;more numerous in legs

Capillaries

Connect arterioles to venules
Walls are one cell thick for efficient exchange
Regulated by precapillary sphincters, adjusting blood flow based on tissue needs
Sinusoids are larger, more permeable capillaries allowing large substances in or out of the blood (in tissues such as red bone marrow, liver, spleen, and pituitary gland)

Exchanges in Capillaries

Sites where materials exchange between blood and surrounding tissue fluid
Movement of gases (and other materials) is by diffusion from a higher to lower concentration
Blood pressure (arterioles) of 30-35 mmHg is higher than the pressure of surrounding tissue fluid, about 2 mmHg.

Filtration of Capillaries

Blood pressure forces plasma and dissolved nutrients from capillaries to the tissue fluid due to higher blood pressure
Pressure decreases in venous capillaries, thereby reducing force

Colloid Osmotic Pressure

Albumin contributes to the colloid osmotic pressure, a pulling pressure
Fluid is pulled into the capillaries at the venous end, collecting waste products from the cells

Tissue Fluid and Lymphatic System

Tissue fluid that returns to circulation helps maintain normal blood volume and pressure
Excess fluid enters lymphatic capillaries where it's recycled as plasma

Hepatic Portal Circulation

Blood from abdominal digestive organs and spleen travels through the liver before returning to the heart
Blood from the stomach, intestines, colon, pancreas and spleen flows through the superior mesenteric and splenic vein, which merge into the hepatic portal vein
The portal vein empties into sinusoids (liver capillaries) where blood is processed before returning to circulation

Liver Functions

Processes nutrients, detoxifies chemicals, synthesizes proteins and bile. Some nutrients may be stored or changed, bilirubin is excreted into bile, and potential poisons are detoxified before returning to the rest of the body
Detoxifies alcohol, and transforms glucose to glycogen when high

Pulmonary Circulation

Blood from the right ventricle is pumped to the lungs via the pulmonary artery
The arteries branch extensively in the lungs into smaller arterioles, then capillaries, surrounding the alveoli where gas exchange occurs
Blood returns to the left atrium via the pulmonary veins

Systemic Circulation

Blood is pumped into the aorta from the left ventricle
The aorta branches extensively throughout the body, into arterioles and capillary networks
Veins collect blood from the tissues and return it to the superior and inferior vena cava, eventually returning to the right atrium

Maintenance of Systemic Blood Pressure

Venous return involves skeletal muscle pump, constriction of veins, and respiratory pump
Heart rate and force contribute
Peripheral resistance, elasticity of arteries, and viscosity of blood influence systemic blood pressure
Loss of blood reduces blood pressure
Hormones also affect blood pressure

Intrinsic Mechanisms of Blood Pressure Regulation

Regulation of blood pressure by the heart itself (Starling's Law)
Regulation of blood pressure by the kidneys (influence blood flow and Renin-angiotensin Mechanism)

Respiratory Pathways

Includes the nasal cavity, pharynx, larynx, trachea, bronchi, lungs, alveoli. Understanding air movement is important in assessing pulmonary function

Pharynx

The soft palate elevates during swallowing to prevent food or saliva from entering the nasopharynx

Nasopharynx

Passageway for air only
Includes the Eustachian tubes, which connect to the middle ear cavities

Oropharynx

Passageway for air and food. Posterior to the oral cavity

Laryngopharynx

Passageway for food and air
Opens anteriorly to larynx and posteriorly to the esophagus
Contractions of the muscular walls of the pharynx and laryngopharynx is part of the swallowing reflex

Larynx

Voice box function: speaking
Air passageway from pharynx to trachea
Made of cartilage to prevent collapse, including the largest thyroid cartilage and uppermost epiglottis
Vocal cords for voice production

Trachea and Bronchial Tree

Trachea is a 4-5" long tube extending from the larynx to the bronchi; it is supported by C-shaped cartilage to allow for esophageal expansion during swallowing
Cartilage supports and maintains the airway open
Mucosa consists of ciliated epithelium with goblet cells, sweeping mucus (and particles) out of the respiratory tract

Right and Left Primary Bronchi

Divisions of the trachea that enter each lung
Further branching forms the bronchial tree
Bronchioles are the smaller branches

Alveoli

Functional units of the lungs
Simple squamous epithelium
Surrounded by elastic connective tissue for exhalation
Surrounded by a capillary network, suitable for efficient gas exchange

Alveoli (Continued)

Each alveolus contains a thin layer of tissue fluid
Surfactant mixes with the tissue fluid in the alveoli

Mechanism of Breathing

Ventilation involves air movement to and from the alveoli
Inhalation and exhalation are controlled by the nervous system and respiratory muscles
Respiratory centers in the medulla and pons regulate breathing
Stimulation for breathing is high CO2

Respiratory Muscles

Diaphragm
External intercostal muscles
Internal intercostal muscles

Inhalation

Diaphragm contracts, flattening and increasing thoracic cavity volume
External intercostals elevate the ribs widening the thoracic cavity
These actions lower intrapulmonary pressure below atmospheric pressure, drawing air into the lungs

Exhalation

Diaphragm and external intercostals relax, decreasing the volume of the thoracic cavity
Elastic recoil of the lungs increases intrapulmonary pressure above atmospheric pressure, expelling air from the lungs

Exchange of Gases

External respiration is the exchange of gases between the lungs and blood
Internal respiration is the exchange of gases between the blood and the body tissues

Transport of Gases in Blood

Most oxygen is carried bound to hemoglobin in red blood cells (RBCs)
Iron in hemoglobin allows for oxygen transport

Pulmonary Volumes

Tidal volume (amount of air inhaled or exhaled in one breath)
Minute respiratory volume (amount of air inhaled or exhaled in one minute)
Inspiratory reserve volume
Expiratory reserve volume
Vital capacity
Residual air volume

Acid-Base Balance of the Blood

Kidneys regulate pH by adjusting secretion levels of elements like hydrogen and bicarbonate based on acidity/alkalinity of the blood

Digestive System Divisions

Alimentary tube (mouth to anus) where digestion and absorption occur
Accessory organs aid the digestive function

Types of Digestion

Mechanical: Physical breakdown of food into smaller pieces
Chemical: Complex food molecules are converted into simpler absorbable molecules (using enzymes)

Structures of Teeth

Function for chewing (mechanical digestion)
Root is rooted in the mandible/maxillae
Pulp cavity contains blood vessels and nerve endings of the trigeminal nerve
Enamel is a hard, resistant surface
Dentin forms the teeth roots

Salivary Glands

Salivary saliva for continuous secretion
Mostly water, small amount of digestive enzymes

Pharynx (Continued)

Oropharynx and laryngopharynx are food passageways connecting the oral cavity to the esophagus
Mechanical movement of food only, no chemical digestion

Esophagus

Muscular tube carrying food from the pharynx to the stomach
No digestion, only peristalsis for movement
Lower esophageal sphincter prevents stomach contents from refluxing

Structural Layers of the Alimentary Tube - Mucosa

Mucosa lining of the digestive tract
Epithelium secretes mucus to lubricate food passage and digestive enzymes

Structural Layers of the Alimentary Tube - Submucosa

Submucosa contains blood vessels and lymphatic vessels, and Meissner's plexus (a network of nerves) of the enteric nervous system for secretion regulation. Parasympathetic (PNS) increases secretions; Sympathetic (SNS) decreases them.

Structural Layers of the Alimentary Tube - External Muscle Layer

Muscular contractions break down food and mix it with digestive juices
Peristalsis moves food towards the anus. Controlled by Auerbach's plexus of the enteric nervous system, where sympathetic (SNS) decreases peristalsis; parasympathetic (PNS) increases it

Serosa

Mesentery, a visceral peritoneum, covers abdominal organs; serous membrane prevents friction during movement
Peritoneum is a continuous serous membrane lining the abdominal cavity

Stomach

Extends from the esophagus to the small intestine
Reservoir for food; digestion proceeds gradually
Mechanical and chemical digestion

Small Intestine

Extends from the stomach to the cecum of the large intestine
Duodenum (first 10 inches)
Jejunum (8ft)
Ileum (11ft)
Digestion is completed, absorption of nutrients (microvilli of intestinal cells aid)

Liver

Produces bile, aiding in fat emulsification (mechanical digestion)

Gallbladder

Stores bile and concentrates it through water absorption

Pancreas

Secretes amylase (starch to maltose), lipase (emulsified fats to fatty acids & glycerol), and trypsin (polypeptides to amino acids)
Produces bicarbonate juice which neutralizes the acidic gastric juices in the duodenum

Absorption

Most absorption takes place in the small intestine through microvilli

Large Intestine - Colon

Colon, 5ft long
Cecum (first portion); Ileocecal valve (no sphincter function) to prevent backflow
Appendix (small, dead-end tube with lymphatic tissue) sometimes removed due to impaction from stool

Large Intestine (Continued)

Ascending colon; transverse colon; descending colon
Sigmoid colon (turns medially and downward)
Rectum (6 inches long)
Anal canal (last portion)
No digestion; water, minerals, and vitamins absorbed from colon contents

Defecation Reflex

Elimination of fecal matter
Involves the coordination of the muscular walls of the large intestine to expel the contents controlled by the spinal cord reflex.

Kidney Functions

Renal blood flow
Formation of urine (Glomerular filtration, Tubular reabsorption, Tubular secretion)
Regulation of blood pressure (Renin-angiotensin mechanism)
Acid-base balance (hydrogen & bicarbonate regulation)
Production of hormones such as erythropoietin (stimulates RBC production)

Renal Corpuscle

Glomerulus surrounded by Bowman's capsule
Bowman's capsule has an inner permeable layer (podocytes) and outer impermeable layer
Glomerular filtrate (formed from the blood in the glomerulus) is in the space between these layers and becomes urine

Renal Tubules

Proximal convoluted tubule (PCT) (in cortex)
Loop of Henle (in medulla)
Distal convoluted tubule (DCT) (in cortex)
Distal convoluted tubules, nephrons, and collecting tubules to form a papillary duct emptying into a calyx of the renal pelvis

Renal Tubule (Continued)

Peritubular capillaries arising from the efferent arterioles surround the renal tubules to absorb reabsorbed materials

Blood Vessels in Kidney

Branches from the abdominal aorta to the renal artery to smaller arteries, arterioles to the afferent and efferent arterioles of the nephron
Afferent arteriole delivers blood to the glomerulus; efferent arteriole delivers blood away from the glomerulus to the peritubular capillaries
Blood flows into the glomeruli, then to efferent arterioles, to peritubular capillaries, to veins within the kidney, to the renal vein, and into the inferior vena cava

Formation of Urine

Glomerular filtration forces fluid from the blood into the Bowman's capsule to form glomerular filtrate
Tubular reabsorption returns necessary materials back into the blood from the filtrate
Tubular secretion (active transport) removes additional waste products to filtrate from blood into the tubules

Other Kidney Functions

Secretion of Renin, Erythropoietin, and Activation of Vitamin D

Urinary Bladder

Reservoir for urine accumulating before elimination
Transitional epithelium lining that can expand without tearing, appearance wrinkled (rugae) in the empty state
Triangular region (trigone) where the openings of the two ureters and the urethra are located
Internal urethral sphincter composed of detrusor muscle fibers surrounding the openings of the urethra

Urethra

Carries urine externally
External urethral sphincter is made of skeletal muscle, under voluntary control

Urination Reflex

Micturition (voiding); spinal-cord reflex for urination.
Stimulus for urination is stretching of the detrusor; bladder can hold up to 800ml of urine

Urination Reflex (Continued)

Stretching (200-400mL) activates sensory nerves; motor impulses to detrusor and cause contraction
Voluntary relaxation of the external urethral sphincter during urination; urine flows out of the bladder via the urethra

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