Download chapter-8-human-organization-student-notes

Biology 12
Human Organization (Chapter 11)
Different levels of organization in the human body
Cells
 Basic unit of structure and function of organisms
Tissues
 Cells of same shape and function join together to form ______
 Examples: nervous tissue, connective tissue, muscle tissue, etc.
 Tissues categorized into 4 major types: __________, ________,
______________, ___________ tissue
a. Epithelial Tissue

 Protects body from injury, desiccation, infection
 Can be specialized to perform other functions as well such as
absorption, secretion, excretion and filtration

1
 Can be organized as __________: single layer of cells
 Can be __________: layers of cells piled on top of each other
 Can be ____________: single layer of columnar epithelium
that looks as though it is stratified but only one cell layer

 Usually ciliated
 The basement membrane is a layer that connects the
epithelium to connective tissue underneath

2
Different Kinds of Epithelial Tissues
1. Squamous epithelium

2. Columnar epithelium

 Have nuclei located at bottom of cells near b.m.
3. Cuboidal epithelium

3
4. Glandular epithelial cells

 Glandular epithelial cells can be a single or many
 If product secreted into ducts are called ___________ glands
 If product secreted into blood then called __________ gland
Cell Junctions

1. Tight junctions

 Involves joining of proteins in cell membranes of cells

e.g. found in epithelial cells of intestine to prevent escape of
intestinal contents into abdomen
 See following diagram
4
2. Gap junction

 Are communication junctions

 Commonly found in cardiac muscle cells and smooth muscle—
to coordinate activity
5
3. Desmosomes (adhesion junctions)

 Plasma membranes held together by proteins or intercellular
filaments
 Serve to allow cell flexibility (i.e. permit stretching of cells
without cells coming apart
b. Connective Tissue

 Functions in binding organs together, support & protection,
insulation, stores fat, produces blood cells
 Typically cells of connective tissues are spaced widely apart and
the space in between the cells is filled with a non-cellular
material called the ________ that can vary in consistency
between liquid to gel
6
Classification of Connective Tissue:
Types of Connective Tissue
 Loose Connective Tissue
 Fibrous connective tissue
(tendons and ligaments)
 Cartilage
 Bone
 Adipose tissue
 Blood tissue
1. Loose Connective Tissue

 Function: to hold organs in place and to bind epithelial tissue
to underlying tissue; also surrounds blood vessels and
nerves

 Fibres can be elastic (for flexibility) or collagen (for strength
and flexibility)
 C.T. helps attach epithelial tissue to other underlying tissues
(e.g. muscle)
7
Light Micrograph of Loose C.T.
2. Fibrous Connective Tissue

 Function: main component of tendons and ligaments
 __________ (bind muscle to bone), ___________ (connect
bone to bone)
8
Figure: fibrous connective tissue
3. Cartilage
 C.T. made exclusively of cells called ___________ which
produce matrix and collagen fibres

 Is found in ears and nose as well as ends of bones in joints
functioning as a cushion and to reduce friction on the
articulating surfaces of these bones
4. Bone

 Mineralized internal matrix by inorganic calcium salts such as
[Ca10(PO4)6(OH)2] or ________________
5. Blood
Functions of Blood:
(i)
(ii)
Carries carbon dioxide and waste materials away from
cells
(iii)
(iv) Contains regulatory agents such as hormones that
influence many activities within the body
9
(v)
(vi) Plays important role in pH, fluid and ionic balance between
blood and tissues
(vii) Has ability to clot to prevent excessive blood loss in injuries
Components of Blood
 Whole blood can be divided into 2 components: plasma and
formed elements
 Made of ______ (55%) and ________________ (or cells) (45%)
 Plasma made of water, inorganic, organic substances
 Cellular component made of ________ (rbc’s), ___________
(wbc’s) and _______________ (platelets) which are made in
the bone marrow of long bones, skull, ribs and vertebrae.
A.Plasma Components

 Proteins (7-8%)

 Nutrients, gases (CO2), hormones, enzymes
10
B. Formed Elements
a) Erythrocytes (Red Blood Cells)







4-5 million per mm3
No nuclei
Contain haemoglobin (red pigment)
Hgb binds oxygen
b) Leukocytes (white blood cells)
 6000-9000 cells per mm3

 Translucent cells

 Fight infections by producing antibodies or by phagocytosing
foreign bodies
11
C) Thrombocytes (Platelets)
 Are fragments of cells called __________________ or giant cells
in bone marrow

 Release chemicals that aid in clotting process
Figure: rbc, platelet and wbc
12
6. Muscle Tissue

 Made of cells specialized for contraction called _____
 Muscle fibers are composed of 2 contractile filaents—_________
and _______ filaments

 3 types of muscle:
(a)Striated or Skeletal Muscle

 Attached to bones of skeleton via __________ (e.g. legs,
arms, head, etc.)
 Muscle cells called _______ and are cylindrical and long

 Fibers have alternating dark and light bands giving them
striated appearance resulting from arrangement of actin and
myosin filaments inside cells making up fibrils
13
Figure: striated muscle structure
(b) Smooth Muscle






Non-striated
Involuntary
Found in organs such as g.i. system and blood vessels
Slower but longer contraction than skeletal muscle
smooth muscle
14
(c) Cardiac Muscle Cells
 Branched/connected cells by desmosomes and gap junctions
at areas called ___________ ______

 Involuntary

 Only found in heart
7. Nervous Tissue
 Includes two types of cells: ________ and __________ cells
Neurons

 Neurons contain following 3 main parts:
15
(a) ____________: conduct impulses to the cell body
(b) ____________________: contains nucleus
(c) ______: conducts nerve impulses away from the cell body;
often covered with a fatty like insulating layer called myelin to
help speed up nerve impulses.

 Many nerve cells bound together form a nerve
Organs

 covered in epithelial tissue

16
Organ Systems

 Often organ systems work with each other (e.g. circulatory and
respiratory or circulatory and endocrine)
 Different organ systems we will be looking at are:
a. Nervous system—made of brain, spinal cord, eye, ear and
nerves
b. Circulatory system—made of heart, blood, and blood
vessels
c. Digestive system—made of esophagus, stomach and
intestines
d. Endocrine system—hormone producing organs and tissues
such as the pancreas, hypothalamus, suprarenal glands, etc.
e. Musculoskeletal system —consists of skeletal muscles and
bones
f. Excretory system—consists of kidneys and associated
structures
g. Lymphatic system—consists of lymph organs and vessels
that play a role in the immune response
h. Reproductive system—consists of ovaries, testes and other
reproductive structures that I am too embarrassed to recite
17
Body Cavities

Thoracic cavity

 bounded by ribs, diaphragm and lower part of neck
18
Abdominal cavity

 From diaphragm to upper part of pelvis and body wall
 Includes, liver, kidneys, stomach, pancreas, intestines and kidneys
Cranial cavity

 Includes mouth, nasal cavities, and auditory cavities
Spinal cavity

Pelvic cavity

19
Homeostasis

 Examples:
o Body temperature stays at around 37 °C
o Blood pH is maintained at a constant level of 7.4
o Blood pressure stays fairly constant
 Regulation of homeostasis is achieved by hormones as well as by
the nervous system that uses a negative feedback control
Negative Feedback Control Of Homeostasis



Has 2 major parts—__________ and a __________ ________
The sensor detects a change in the internal conditions of the body
and the control centre directs a change to restore conditions to
normal



Thus, the control centre has negated the initial stimulus that
activated the sensor—hence the name “negative feedback
control”
For example, blood pressure regulation
20
 When blood pressure is high, baroreceptors in major artery of
neck sense it (__________)
 Baroreceptor sends signal to the brain stem (________________)

 This lower blood pressure tells the baroreceptors in the arteries
that the blood pressure is not high anymore so no message goes
back to the control centre to make any more changes to blood
pressure—i.e. negative feedback.

21
Controlling Body Temperature
 Example of fluctuating feedback control
Cooling Body Temperature Below Normal
 Receptor in __________________ (structure in brain) senses
temperature change of blood

 errector pili muscles become erect trapping layer of insulating air
 if further blood temperature drop, nerve impulses sent to muscles
→ shivering → raises body temperature
Overheating of Body

 sweat glands also activated → evaporation of sweat
22
Positive Feedback Control Of Homeostasis

 less common than Negative Feedback control discussed above

 in childbirth, stretching of the smooth muscles of the uterus
causes increased production of the hormone oxytocin which
increases the rate of uterine muscle contractions causing even
more oxytocin to be released and so this continues until the baby
is born

23