2. cont TO CELL, TISSUES, MEMBRANE

CELL AND TISSUES

WAN NAPISAH BINTI WAN OMAR

PASSIVE TRANSPORT

Diffusion

Osmosis

Filtration

Movement Of Materials Across Cell Membranes

Diffusion:

❖ -physical process whereby molecules of gases, liquids or solid particles
spread themselves through medium.

❖ -when solid particles are dissolved within a fluid, they are known as
solutes.

❖ -molecules will diffuse more quickly in gases and more slowly in solids.

❖ -Movement of molecules increases with an increase in temperature.

❖ When molecules eventually distribute themselves within the space
available it is called equilibrium.

EXAMPLES

1. -if you saturates a wad of cotton with ammonia and places it in a far corner of
a room, the entire room will soon smell of ammonia. Air currents quickly carry
the ammonia fumes throughout the room.

2. -place a pair of dye crystals on the bottom of a water-filled beaker. Eventually
the crystals will uniformly permeate and color the water. This diffusion
process will take quite a while especially if no one stirs, shake or heats the
beaker.

3. -a dye crystal placed on an ice cube moves even more slowly through the ice.
Diffusion of dye can be accelerated by melting the ice.

SUMMARY

Molecules in the various media (gas, liquid and solid) depends on the
distance between each molecule and how freely they can move.
1. In gas – molecules can move more freely and quickly.
2. Liquid –molecules are more tightly held together.
3. In solid – molecular movement is highly restricted & very slow.

To maintain homeostasis

Oxygen diffuse from an
alveolus (greater
concentration) → across the
blood capillary membrane →
enters the fluid surrounding a
cell and then into the cell
(lesser concentration).



OSMOSIS

-is a process of movement of solvents
through a semi-permeable membrane(e.g.
cell membrane) from a region of lower
solute concentration to higher solute
concentration.

-a selective permeable membrane is any
membrane through which some solutes
can diffuse, but others cannot.

OSMOSIS

1. Pressure exerted by the water
molecules within the casing at
equilibrium is called osmotic.

2. If a red blood cell is put into blood
plasma, which have the same
number of sodium particles as a
RBC, the osmotic pressure of the
RBC and plasma are the same –
isotonic solution

OSMOSIS

2. If a RBC is put into freshwater,
which has fewer sodium
particles than the RBC, water
will rush into RBC. Freshwater
represents a hypotonic
solution.

OSMOSIS

3. If a RBC put into seawater, which
has more sodium particles than
the RBC, water will leave the
RBC to dilute the seawater.
Seawater represents a
hypertonic solution.



OSMOSIS

The health café professional must know which type of solutions are used in
various circumstances.
When a physician orders intravenous fluids, the patient’s condition will
determine what type of solution is ordered.
✓ Most IV fluids are isotonic solutions.
✓ Hypertonic solutions are used for patients with edema.
✓ Hypotonic solutions are used for patients with dehydration.





FILTRATION

✓ Is the movement of solutes and water across a semipermeable
membrane.

✓ This result from some mechanical force such as blood pressure or
gravity.

✓ The solutes and water move from an area of higher pressure to an
area of lower pressure to maintain homeostasis

✓ Such filtration takes place in the kidneys.

✓ The process allow larger protein molecules to remain within the body
and smaller molecules to be excreted as waste.



ACTIVE TRANSPORT

✓ Process whereby molecules move across the cell membrane from an
area of lower concentration against a concentration gradient to an area
of higher concentration.

✓ The food we eat must be transformed into another form of chemical
energy that allows cells to maintain, repair, and reproduce.

✓ ATP is supplied by cell metabolism.

PHAGOCYTOSIS

Phagocytosis or “cell eating”, is quite similar to pinocytosis.
Pinocytosis – the substances engulf by the cell membrane are in solution.
Phagocytosis – substances engulf are within particles.



PINOCYTOSIS

✓ Pinocytosis or “cell drinking” –
engulf large molecules in solution.

✓ Cell ingests the nutrient for its own
use.

DISORDER OF CELL STRUCTURE

Cell may decrease in size – atrophy – due to aging or disease.

Cell increase in size– hypertrophy – increase in workload.

Cell increase in number – hyperplasia – related to hormonal stimulation.

Cell can change into another type of cell called metaplasia – protective
response to a stimulus such as smoking.

Dysplasia is the change of size, shape. This type of cell alteration usually
progress to neoplasia. Neoplasia is changes in cell structure that occur in
an uncontrolled growth pattern.

DISORDER OF CELL STRUCTURE

Hypoxia - a decrease in the amount of oxygen in the blood flow to cellular
structure.
Anoxia – a lack of oxygen flow to cellular structures, most commonly cause
death in cells. Bacterial toxins or viruses can also result in cell death.
Congenital defects alter cell structure – cause by unknown factor, but some
caused by genetics, chromosomal alterations and environmental factors.

TUMOR

✓ If the pattern is interrupted by an abnormal and uncontrolled growth of
cells.

✓ Also known as neoplasm.
✓ Divided into two groups:
1. Benign – cell confined to the local area example; wart or papilloma, can

be surgically removed.
2. Malignant – cancer.

CANCER

Cancerous or malignant tumors continue to grow, crowding out healthy
cells, interfering with body functions and drawing nutrients away from body
tissues.
Can spread to other parts through a process called metastasis.
Cancers are group into 6 major categories: carcinoma, sarcoma, myeloma,
leukemia, lymphoma and mixed type.

CARCINOMA – internal or external lining of the body

SARCOMA – connective tissue such as bones, tendons, cartilage, muscle

MYELOMA – occurs in plasma cells of bone marrow

LEUKEMIA – cancer of bone marrow



CHEMOTHERAPY

Treatment of cancer depends on
the type of tumor and where it is
located.
Surgery, radiation, use of drugs
(chemotherapy), immunotherapy
and laser.

TISSUES

LEARNING OUTCOMES

After studying this section, student should be able to:
1. Describe the structure and functions of epithelial, connective and

muscle tissue.
2. Outline the structure and functions of epithelial and synovial

membranes.
3. Compare and contrast the structure and functions of exocrine and

endocrine glands.



EPITHELIAL TISSUE

This tissue type covers the body and lines cavities, hollow organ and tubes and
glands.
Function :
1. Protection of underlying structures from, dehydration or chemical and mechanical

damage.
2. Secretion.
3. Absorption.
Type:
1. Simple: single layer of cells
2. Stratified: several layers of cells



Simple Epithelium (squamous, cuboidal, columnar)

Squamous epithelium:
❖ The cell fit closely together like paving stones, forming a thin and very

smooth membrane across which diffusion occurs easily.
❖ It forms the lining:
✓ Heart – known as endocardium
✓ Blood vessels, lymph vessels – known as endothelium
✓ Alveoli of the lungs
✓ Collecting ducts of nephrons in the kidneys



Cuboidal Epithelium

-consists of cube-shape cells fitting closely together and lying on a
basement membrane.
-forms the wall of kidney tubules
-found in some glands such as the thyroid.
-actively involved in secretion, absorption, and/or excretion.

Columnar Epithelium

✓ -formed by a single layer of tall, thin cells on a basement membrane
✓ -lining of the stomach is formed from simple columnar epithelium

without surface structures covered with microvilli
✓ -microvilli – absorption of nutrients from small intestine.
✓ -in trachea –contains goblet cells that secrete mucus.
✓ -in uterine tubes – ova propelled along towards the uterus by ciliary

action.



STRATIFIED EPITHELIUM

✓ -consist of several layers of cells of various shapes.
✓ -main function – protect underlying structures from mechanical wear

and tear
✓ -two main types:
1. Stratified squamous – keratinized stratified, non-keratinized stratified
2. Transitional – several parts of the urinary tract, including bladder,

allows for stretching as the bladder fills.

CONNECTIVE TISSUE

Most type of connective tissue have a good blood supply.
Function :
✓ Binding and structural support
✓ Protection
✓ Transport
✓ Insulation.

Cells In Connective Tissue

The range of cell types involved includes :
✓ Fibroblasts
✓ Fat cells
✓ Macrophages
✓ Leukocytes
✓ Mast cells





Loose (areolar) connective tissue

Found in almost every part of the body, provide elasticity and tensile strength.
Connects and supports other tissues, for example:
✓ Under the skin
✓ Between muscles
✓ Supporting blood vessel and nerves
✓ In the alimentary canal
✓ In gland supporting secretory cells

Cont.

❑ Adipose tissue
-consist of fat cells (adipocytes), containing large fat globules. There are two types:
white and brown.
❑ Reticular tissue
-contain reticular cell and white blood cell (monocytes and lymphocytes).
-found in lymph nodes and lymphatic organs
❑ Dense connective tissue – fibrous tissue, elastic tissue.
✓ Fibrous tissue – covering organ e.g kidneys, lymph nodes and brain
✓ Elastic tissue – large blood vessel walls, trachea and bronchi and lungs.
❑ Cartilage –reinforce by collagen and elastic fibres. There are 3 types: hyaline

cartilage, fibrocartilage, and elastic fibrocartilage.

BONE

❑ Bone cells (osteocytes) are surrounded by a matrix of collagen fibres
strengthened by inorganic salts, especially calcium and phosphate.

❑ 2 types:
1. Compact bone
2. Spongy or cancellous bone

MUSCLE TISSUE

➢ -able to contract and relax, providing movement within body.
➢ -muscle contraction requires a rich blood supply providing sufficient

oxygen, calcium, and nutrients and removing waste product.
➢ -there are 3 types:
1. Skeletal muscle
2. Smooth muscle
3. Cardiac muscle