BIO1000A-Introductary Life Sciences
By Amatullah Chiosa
“Systems are used in the body of a human being to enable it to carry out bodily functions and make
sure that the body is kept alive. Understanding these systems in animals and human beings can
enable us to mimic their function in medicine and keep them alive as doctors. This understanding
is not simple but has been made into a comprehensive and compact summary in this document ”
CONCEPTS COVERED
Respiratory system
Circulatory system
Temperature and metabolism
Homeostasis
Nervous system
Muscles
Endocrine system
Reproductive system
,Physiological systems of animals
The main of the body is to keep the individual alive for as long as possible. In order for this to happen;
certain systems have to be put in place so that the body obtains the right nutrients, has the ability to get
rid of waste and breathe in required gasses and take out toxic substances. These systems are divided and
represented below:
•consists of •consists of •consists of •consists of
bones,tendons, skeletal, smooth mouth, stomach, trachea, lungs,
ligaments and and cardiac liver, pancreas pharynx,
cartilage muscles and intestines bronchioles and
bronchi
muscular respiratory
skeletal system digestive system
system system
•consists of •consists of blood, •consists of bone •consistsof
neurons, brain, the heart and marrow, thymus, urethra, urinary
spinal chord and blood vessels spleen, lymph tract and bladder
sensory organs nodes and lymph and kidneys
vessels
circulatory lymphatic and excretory
nervous system
system immune system system
•consists of skin, •consists of •consists of
nails and hair(the hormones and ovaries, ovum,
outer covering) glands testes
intergumentary endocrine reproductive
system system system
Another important aspect is in regard to the environment cells are found in. The extracellular environment
refers to the interstitial fluid, the fluid found between cells whereas the intracellular environment refers
to any place within the cell.
, Circulatory system
The circulatory system is a system that works in transportation of nutrients, waste, oxygen, and
carbon dioxide. In addition, it helps to transport heat energy and chemical energy as well as defend
the body using hormone control and provides the body of some animals its structure.
Types of circulatory systems
No circulatory Open systems Closed systems
system
Contain no circulatory Unspecialized Specialized system Specialized one- Specialized two cycle
system and thus do not system Lymph and cycle system system
have blood. They use the fluid hemolymph are The heart has one The heart as two
in their coelom or circulated through pump and circulates pumps and circulates
Example: single-celled pseudocoelom the blood vessels and once. through the heart twice
organisms; flatworms empties into blood for every time it goes
e.g., roundworm, cavity e.g., fish, through the lungs.
peanut worms, earthworms
cnidarians e.g., insects, e.g., birds, mammals
mollusks, sea-
squirts; hagfish
Vertebrate circulatory systems
Generally, vertebrates have closed circulatory systems. They differ in the number of chambers
and circuits of blood flow. These are expressed below:
Fishes: heart has two chambers and a single circuit of blood flow.
Amphibians: heart has 3 chambers and two circuits of blood flow (some mixing occurs).
Reptiles(not birds): heart has 3 chambers and two circuits of blood flow(no mixing due to
presence of septum).
Mammals and birds: heart has 4 chambers and two circuits of blood flow.
Blood vessels
Veins: Transport oxygenated(oxygen-rich) blood
Artery: Transports deoxygenated(oxygen-poor) blood
Capillary: Centre of exchange in the organs
Vena cava (superior and inferior): Transports oxygenated blood towards the heart from the blood
vessels
Pulmonary artery: Transports deoxygenated blood to the lungs from the heart
Pulmonary vein: Transports oxygenated blood away from the lungs to the heart
Aorta: Transports oxygenated blood away from the heart to the blood
vessels in the body.
Precapillary sphincters: Muscle rings around arteries that contract and relax so that the
exchange of blood is controlled.
, Mammalian Heart Structure and Components
Valves: function in preventing the blood from flowing in the opposite direction
Atrioventricular valve(between ventricles and atria)
-tricuspid : on the right side -bicuspid: on the left side
Semilunar valves(between ventricles and arteries)
-pulmonary valve: on the right side -aortic valve: on the left side
Chordae tendinea: Heart strings that are connected to papillary muscles and atrioventricular valves
prevents eversion of the valves.
heart murmur: a defect in one or more valves which causes an identifiable hissing sound heard by
a stethoscope.
RIGHT ATRIUM: LEFT ATRIUM:
collects oxygenated blood from the lungs the superior and inferior vena cava
through the aorta. transport deoygenated blood to this area.
RIGHT VENTRICLE: LEFT VENTRICLE:
transports deoxygenated blood to the transports oxygenated blood to body
lungs via the pulmonary artery. tissues via the aorta.
Pulmonary system: set of blood vessels flowing to and from the lungs
Systemic system: set of blood vessels flowing to and from the organs of the body
Q:Why is the left side of the heart thicker than the right side?
A: the left ventricle pumps blood around the body so it has a noticeably thicker wall myocardium.
