Transcript human physiology

HUMAN PHYSIOLOGY
RHODA OLADAPO
IB BIOLOGY 2 SL.
SUB-TOPICS
•
DIGESTION
•
THE BLOOD SYSTEM
•
DEFENCE AGAINST INFECTIOUS DISEASES
•
GAS EXCHANGE
•
NEURONES & SYNAPSES
•
REPRODUCTION
DIGESTION
This is the break down of large molecules.(usually
food. Duhh!) into the simplest and smallest molecular
forms by chemical reactions.
Reasons for Digestion
•
For the conversion of large food substances into
smaller molecules to pass through the cells in
the wall of the gut
•
Break down of proteins and other
macromolecules so that the human bod can
obtain all the subunits that it needs to build up its
own macromolecules.
ENZYMES IN DIGESTION
Enzymes are used to speed up the process of
digestion. These enzymes are all made in glands and
secreted into the gut, where they mix with the food.
Large
Molecule
Enzyme
Small
molecule
Starch
Amylase
Maltose
Protein
Protease
Amino acids
Lipids
lipase
Fatty acids +
glycerol
Enzyme
Secreting glands
Region
enzyme works
pH of region
where enzyme
works
Amylase
• Salivary glands
• Pancreas
Mouth
Small intestine
6.0 - 7.0
7.0 – 8.3
Protease
• Stomach wall
• Pancreas
Stomach
Small intestine
1.0 - 3.5
7.0 - 8.3
Lipase
• Pancreas
Small Intestine
7.0 - 8.3
STRUCTURE OF THE DIGESTIVE SYSTEM
The part of the human body used for
digestion can be described as a tube. The
wall of the tube is made of living tissues .
Tissues in the digestive system and their functions
Tissue
Function
Muscle fibers
To push the food along
Secretory cells
To produce mucus for
lubrication and enzymes
for digestion.
Epithelial cells
Forms the inner lining and
absorbs digested food.
Side note:
The gall bladder is connected to the liver.
The liver is connected to the stomach.
The purpose f the liver is to make bile which is a
digestive fluid stored in the gall bladder.
STRUCTURE & FUNCTION OF THE STOMACH
• The wall of the stomach is called a glandular. It secretes
mucus, hydrochloric acid and protease
• Hydrochloric acids kills the bacteria in the food we
swallow
• Protease secreted in the stomach is called pepsin which
begins the process of denaturing proteins by breaking
up polypeptides into shorter chains of amino acids.
• The elasticity of the stomach allows for the swallowing of
large meals.
• The wall of the stomach is muscular which contracts to
squeeze, mix and break food into smaller pieces.
CHURNING
STRUCTURE & FUNCTION OF THE SMALL INTESTINE
Longitudinal
region
Circular
Regional
DIFFERENCE BETWEEN
ABSORPTION & ASSIMILATION
Absorption: is the process of taking in
substances. It happens in the small intestine.
Structures called villi are adapted to carry out
this process.
Assimilation: is the process when substances
derived from food becomes part of the structure
of the body.
STRUCTURE OF A VILLUS
THE TRANSPORT SYSTEM
MAIN TRANSPORT SYSTEM IN HUMANS CONSISTS OF:
• Blood
• The heart to pump it
• Blood vessels through which it is pumped.
blood vessels
arteries
Capillaries
Veins
Pulmonary Circulation: To and from lung
Systematic circulation: To and from all other organs
including the heart itself.
STRUCTURE OF THE HEART
CONTROL OF THE HEART BEAT
• Contraction is myogenic ( the muscle in the heart stimulates its contraction )
• The region of the heart that sets the overall pace of contraction is the PACEMAKER ( a small group
of muscle cells in the wall of the right atrium)
• Branches of two nerves are connected to the pace maker which brings signals from a region in the
medulla of the brain
• Impulses from one of the nerves causes the pacemaker to increase the rate while the other nerve
causes it to decrease
• The pacemaker also responds to adrenalin causing an increase in heart rate.
The Structure of the Blood
•
•
•
•
•
Plasma: A fluid between blood cells.
Platelets: Cells that circulates in the blood which clots to keep us from bleeding
Erythrocytes: Red blood cells
Leukocytes: White blood cells
Phagocytes: Cells that engulf foreign materials
DEFENCE AGAINST INFECTIOUS DISEASE
• The skin and mucous membrane form a primary defense
against pathogens that cause infectious diseases
• Cuts in the skin are sealed by blood clotting
• Clotting factors are released from platelets.
• Ingestion of pathogens by phagocytic white blood cells gives
non-specific immunity to diseases
PRODUCTION OF ANTIBODIES
• Antibodies are produced by lymphocytes n response to specific antigens
WHY ANTIBIOTICS DO NOT WORK ON VIRUSES
• Viruses lack a metabolism and therefore cannot be treated with antibiotics
• Some bacteria are resistance to antibiotics because they have multiple resistance.
GAS EXCHANGE
• Ventilation maintains concentration gradient of Co2 and O2 between air in alveoli and
blood flowing in adjacent capillaries.
Cells in the lungs
• Type I pneumocytes: Are
extremely thin alveolar cells
that are adapted to carry out
gas exchange
• Type II Pneumocytes: Secretes
a solution containing surfactant
that creates a moist surface
nside the alveoli to prevent the
sides of the alveolus adhering
to each other by surface
tension.
PROCESS IN WHICH VENTILATION OCCURS
• Air is carried to the lungs in the
trachea and bronchi and then to
the alveoli in bronchioles
• Muscle contractions cause the
pressure changes
• Inside the thorax that force air in
and out of the lungs to ventilate
them.
• Different muscles are required for
inspiration and expiration.
NEURONS AND SYNAPSES
• Neurons transmits electrical impulses
• A nerve impulse is only initiated if the threshold potential is reached
• Neurons pump sodium nd potassium ions
across ther membranes to generate a resting
potential.
• An action potential consists of depolarization
and repolarization of the neurons.
• Nerve impulses are action potentials
propagated along the axons of neurones.
• Propagation of nerve impulses is a result of all
local currents that cause each successive part
of the axon to reach the threshold potential.
Synapses are junctions between neurons and between neurones and receptors
When presynaptic neurones are depolarized, they release a neurotransmitter into the synapse
Hormones, homeostasis and
reproduction
• Insulin and glucagon are secreted by beta and alpha cells of the
pancreas respectively
• Leptin is secreted by cells in adipose tissue and acts on the
hypothalamus of the brain to inhibit appetite
• Melatonin is secreted by pineal glands to secrete circadian
rhythms (sleeping).
• Thyroxin is secreted by the thyroid gland to regulate the
metabolic rate and to help control body temperature.
• Human reproduction involves the fusion of a sperm from a male and an egg from a female
• The hormone present in the male reproductive system is the testosterone while estrogen and
progesterone are present in females.
• At puberty, the production of testosterone increases while estrogen and progesterone during
pregnancy or menstruation.
SPERMATOGENESIS AND OOGENESIS
IVF( In-vitro fertilization)
FEMALE REPRODUCTIVE SYSTEM AND THE MENSTRUAL CYCLE
a part of the female system known as the
hypothalamus is the regulatory center of the
menstrual cycle. FSH and LH are the
hormones involved in this process and the
target tissues for these hormones are the
ovaries.
MALE REPRODUCTIVE SYSTEM