CH 2: Body Systems - Cardiovascular, Urinary, Digestive, Respiratory, Nervous, Endocrine

Cardiovascular System

also called circulatory system, transports blood, oxygen, nutrients, waste throughout body

made of heart, blood, blood vessels

Heart

muscular organ located in the chest (mediastinum)

pumps blood through body to deliver oxygen and remove waste

Arteries/Arterioles

thick-walled vessels that carry blood away from the heart

proper oxygenated blood to body

Arterioles

small branches of arteries

Veins/Venules

thin-walled vessels that carry blood towards the heart

transport deoxygenated blood, contain valves to prevent backflow

Venules

small veins that connect capillaries to larger veins

Capillaries

microscopic vessels connecting arteries and veins

allow oxygen, nutrients, waste exchange between blood and body tissues

Endocardium

inner lining of the heart chambers and values

smooth surface reduces friction and protects tissue

Myocardium

thick muscular middle layer of heart

responsible for pumping action of heart

Pericardium

outer protective membrane around heart

reduces friction and protects heart from surrounding organs

Describe the process of how the heart works

right atrium received blood from body via superior and inferior vena cava → right ventricle pumps blood through pulmonary valve to lungs via pulmonary artery for O2 exchange → left atrium receives O2 blood from lungs through pulmonary veins → left ventricle pumps O2 blood through aortic valce into aorta to the body → heart valves ensure blood flows in one direction

What is the only vein in the body that pumps oxygenated blood?

pulmonary veins

What are the valves of the heart?

tricuspid, pulmonary, mitral (bicuspid), aortic

Pulmonary Circulation

moves blood between heart and lungs to exchange CO2 for O2

Systematic Circulation

moves oxygenated blood from heart to body and returns deoxygenated blood to heart

Sinoatrial (SA) Node

initiates electrical impulse in the heart

Describe the process of the heart’s electrical system working to pump blood

SA node initiates electrical impulse → impulse goes to atrioventricular (AV) node which delays it slightly to allow the atria to contract → impulse moves through bundle of His and bundle branches down to ventricular blood → impulse spreads to Purkinje Fibers, causing ventricles to contract and pump blood

What is the sequence of events that allows the heart to contract called?

the cardiac cycle

Urinary (Renal) System

role in maintaining body’s internal balance by removing waste, controlling fluid levels, regulating electrolytes

Kidneys

two bean-shaped organs located on either side of the spine near the lower back

filter blood to remove waste, regulate water and electrolyte balance, produce urine

Ureters

two narrow tubes that extend from each kidney to the bladder

carry urine from kidneys to bladder through rhythmic muscular contractions

Urinary Bladder

muscular hollow sac located in the pelvic cavity

temporarily stores urine until ready to be expelled

Urethra

small tube that extends from the bladder to outside of body

carries urine out of body, longer in males

Urinary Meatus

external opening of urethra

Overall Function of Urinary System

eliminate waste, which regulates blood pressure, pH balance, RBC production through kidney-released hormone erythropoietin

Gastrointestinal (Digestive) System

responsible for breaking down food into nutrients the body can use for energy, growth, repair

Alimentary Canal

series of organs and pathways that assist with digestion

Mouth (Oral Cavity)

responsible for initiating digestion, both mechanical (chewing) and chemical (saliva)

Pharynx

throat, passageway for food between oral cavity and esophagus

shared between respiratory and digestive systems

Esophagus

muscular tube connecting mouth to stomach, uses wave-like contractions to propel food into stomach

Peristalsis

wave-like contractions that propel certain things through the body

Stomach

below diaphragm in LUQ of abdominal cavity

received food from esophagus and continues breakdown using gastric juices, propels food to small intestine

Rugae

folds in the stomach that allow expansion

Small Intestine

takes up most space in abdominal cavity

primarily responsible for nutrient absorption

What are the main sections of the small intestine?

duodenum, jejunum, ileum

Large Intestine (Colon)

completes absorption and forms feces from solid waste products

Cecum

part of the large intestine that connects to ileum where appendix is

What are the main sections of the large intestine?

cecum, ascending colon, transverse colon, descending colon, sigmoid colon

Rectum

end of colon that stores feces until defecation

Anus

end of rectum

Liver

in RUQ of abdomen

produces bile to break down fats

Gall Bladder

inferior to liver, connects to duodenum

stores bile

Pancreas

posterior to stomach, connected to duodenum

produces enzymes that aid in digestion, produces insulin and glucagon to regulate blood sugar

Respiratory System

responsible for taking in O2 and expelling CO2 (metabolism waste product)

Nose

made of bone, skin, cartilage

primary entry point for air, filters dust and debris using cilia

Larynx (Voice Box)

located above trachea

produces sound, prevents food and liquids from entering airway

Trachea (Windpipe)

tube that extends from larynx and divides into 2 bronchi

carries air to lungs, lined with cilia to trap and expel particles

Lungs

2 cone-shaped organs located in thoracic cavity

responsible for gas exchange

right lung has 3 lobes, left lung has 2, both surrounded by pleura

Gas Exchange

O2 moves from alveoli sacs in the lungs to the surrounding capillaries, CO2 passes from blood to alveoli to be exhaled

Pleura

protective membrane around the lungs

Why does the right lung have more lobes?

to make room for the heart on the left side of the chest

Describe the steps of how the respiratory system works

inhalation (inspiration): air enters nose/mouth and travels down pharynx to larynx to trachea to lungs → gas exchange (external respiration) → exhalation (expiration): diaphragm relaxes forcing CO2-containing air out of lungs → internal respiration: O2 within bloodstream binds to hemoglobin in RBCs, transported to body tissues, CO2 produced by cells and sent back to lungs

Nervous System

coordinates all body activities, allows body to respond to internal and external stimuli, enables thought, emotion, memory, and movement

Central Nervous System (CNS)

brain and spinal cord

the control center, receives, processes, and sends out information

Peripheral Nervous System (PNS)

all nerves outside brain and spinal cord

conencts CNS to the rest of the body, transmits signal to and from organs and tissues

Brain

located within skull, composed of four lobes

controls thoughts, emotions, judgement, voluntary movement, most bodily functions

What are the four lobes of the brain?

frontal, parietal, occipital, temporal

Spinal Cord

extends from base of the brain through vertebral column

carries nerve impulses to and from brain, communication highway

Peripheral Nerves

12 pairs of cranial nerves, 31 pairs of spinal nerves

transmits signals between brain, spinal cord, and body

Neuron

functional unit of nervous system

transmits electrical and chemical signals

Dendrites

receive incoming messages from other neurons

Nucleus

directs the neuron’s activities

Cytoplasm

produces energy and neurotransmitters

Axon

sends impulses away from cell body to other neurons/muscles

Somatic Nervous System

controls voluntary body movements

Afferent Neurons

carry signals to CNS

Efferent Neurons

send motor commands from CNS to muscles

Describe the process of neural communication

neuron generates electrical impulse when stimulated → neurotransmitters (chemical messengers) released at the end of the axon

Endocrine System

network of organs and glands that produce, store, and release hormones

Hormones

chemical messengers that regulate body functions

travel through bloodstream to target cells, influence growth, metabolism, reproduction, mood

Exocrine Glands

release hormones or secretions into ducts, deliver products directly to target areas

Endocrine Glands

release hormones directly into the bloodstream, allow hormones to travel throughout the body to specific target organs and tissues

Pituitary Gland

at the base of the brain

known as the “master gland”, controls other glands and regulates growth, metabolism, reproduction

Pineal Gland

deep within brain

produces melatonin

Thyroid Gland

front of the neck

regulates metabolism, body temperature, energy through hormones T3 and T4

The names of T3 and T4 are…

triiodothyronine and thyroxine

Parathyroid Glands

behind the thyroid gland

regulate calcium and phosphorus levels in blood

Adrenal Glands

on top of each kidney

produce adrenaline (epinephrine) for “fight or flight” responses and cortisol for stress and metabolism regulation

Ovaries

lower abdomen

produce estrogen and progesterone, which regulate menstrual cycle and support pregnancy

Testes

scrotum

produce testosterone, which influences sperm production and male characteristics

Thymus

role in immune system development by producing thymosin (helps in T-cell production)

Describe the general process for how the endocrine system works

hormone production: glands release hormones into bloodstream → target interactions: hormones bind to specific receptors on target cells → response activation: target cells perform specific action → feedback mechanism: uses feedback loops to maintain balance