Bronchopulmonary segments are the smallest surgically resectable subdivisions of the lung lobes. [1] They are pyramid-shaped regions supplied by a segmental bronchus and artery, and separated from adjacent segments by connective tissue septa. [2] Understanding bronchopulmonary segment anatomy is clinically significant for surgical resection, localizing pathology, and radiological interpretation. [3]

1. QUESTION: DESCRIBE THE BROCHOPULMONARY
SEGMENTS OF THE RIGHT AND LEFT LUNGS AND DISCUSS
IT CLINICAL SIGNIFICANCE CLINICAL SIGNIFICANCE
DEFINITION: a bronchopulmonary segment is the smallest 1) Surgically resectable with little or no bleeding
surgically resectable subdivision of the lobes of the lungs, depending on the lung surgeon.
supplied exclusively by a tertiary (segmental) bronchus and
2) Inflation of any malignancy can be confined to a
the corresponding tertiary branch of the pulmonary artery
particular segment because of the intersegmental
(segmental pulmonary artery)
septa.
CHARACTERISTICS OF EACH BRONCHOPULMONARY
3) For Radiological interpretation: once u have a
SEGMENT
knowledge of the BP segment
1) SHAPE: Pyramidal-shaped, with the apex facing the
4) Segmental Atelectasis whereby air is not getting
lung root and their bases on the pleural surface.
into a blocked BP segment. However other
segments may compensate for this.
2) Separated from adjacent segments by connective
tissue septa. ANATOMICAL SIGNIFICANCE:
3) Supplied independently by a segmental bronchus
5) Forensics purpose – as in determining of the cause
and a segmental pulmonary artery
of victim’s death is via say, atelectasis or
4) Drained by intersegmental parts of the pulmonary suffocation
veins that lie in the connective tissue.
5) Named according to the segmental bronchi
supplying them
6) NUMBER: 10 on the right and 8-10 on the left
7) Surgically Resectable.
NAMES OF THE BRONCHOPULMONARY SEGMENTS
FOR THE RIGHT LUNG: the names of the bronchopulmonary
segment include:
1) FOR THE SUPERIOR LOBE: apical, posterior and
anterior (APA) BP segments
2) MIDDLE LOBE: Lateral and medial BP segments
3) INFERIOR LOBE: superior, anterior basal, posterior
basal, medial basal and lateral basal BP segments.
FOR THE LEFT LUNG:
1) SUPERIOR LOBE: apical, posterior, anterior,
superior and inferior (APASI) BP segments. The
apical and posterior segments r sometimes called
apicoposterior segment. The superior and inferior
segments r stms called the lingular segement.
2) INFERIOR LOBE: superior, anterior basal, posterior
basal, medial basal and lateral basal BP segments.
Anterior basal and medial basal r sometimes
combined into anteromedial basal BP segment.
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2. QUESTION: DESCRIBE THE CELL CYCLE, USE ITS KNOWLEDGE - Cell growth also occurs here.
TO CHARACTERIZE BODY CELLS
- Chromosomes start to become condensed.
DEFINITION OF CELL CYCLE:
- Mitotic spindles begins to form
It is a series of events that take place in a cell leading to its
division and duplication (replication). M phase
In prokaryotic cells, the cell cycle occurs via a process termed - Period of cell division
binary fission. In eukaryotes, the cell cycle can be divided in
- There of 2 types of cells division: mitosis and meiosis.
two periods: interphase and the mitosis (M) phase.
PHASES OF CELL CYCLE IN EUKARYOTES
- In both cases a cell growth stops, and the cell divides
to form daughter cells with each of the replicated
1) INTERPHASE: which is divided into 3 chromosomes entering each daughter cells.
a. G1 phase - Is subdivided into prophase, prometaphase,
metaphase, anaphase and telophase.
b. S phase – DNA synthesis phase
- In mitosis these sub-phases occur once to give 2
c. G2 phase daughter cells. In meiosis these sub-phases occur
twice to produce 4 daughter cells.
2) G0 phase - a SPECIAL interphase period
- IMPORTANCE:
3) M PHASE (mitotic phase)
o To form germ cells
G1 PHASE (gap 1 phase):
o To form tissues and organs
- The first phase within interphase, from the end of the
previous M phase until the beginning of S phase. o To ensure continuous replacement cells with
limited life-span.
- Increased synthesis of new cell organelles and
materials needed for DNA replication in S phase. G0 phase
- Cell metabolic rate is high - A dormancy phase where the cell has left the cycle
and stopped dividing.
- Cells growth occurs
- It is a modified G1 phase.
- DURATION: highly variable, even among different
cells of the same species. - It doesn’t mean that the cells are inactive; the cell r
still able to carry out their main life’s functions. For
S phase e.g. a healthy liver cell is still able to break down Hb,
synthesize proteins (albumin, angiotensinogen …etc),
- Phase of DNA, and consequently, chromosome
and so on. It does not need to synthesize proteins for
replication.
S phase or for M phase (meaning it does not enter G1
and G2 phase respectively) and consequently, it does
- Here, xsome is not visible (because they have
not enter S and M phases.
stretched out/ extended).
CLASSIFICATION OF CELLS BASED ON THE ACTIVITY OF THE
- DURATION: very short, [because the base pairs are
CELL CYCLE
now exposed – due to stretching of chromosomes –
and r sensitive to drugs or mutagens such as - LABILE CELLS: goes through cell cycle spending little
nicotine]. or no time in the G0 phase, in order to replace lost cell
or to maintain the turn-over of cells. E.g. skin cells,
G2 phase:
blood cells, cells in the GIT, basal cells… etc.
- Gap between DNA replication (or synthesis) and
mitosis (M phase). - STABLE CELLS: tend to stay in the G0 phase especially
in the case where the tissue has grown to its full size.
- Also there is intensive cellular synthesis particularly of If some of the cells in the tissue r removed or injured,
materials (like microtubules) needed for the M phase the remaining healthy cells undergo cell division to
replicate lost/injured cells. After fully replacing the
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3. damaged cells, the healthy cells go back to the G0
phase. E.g. liver cells, smooth muscle cells, skeletal
muscle (limited regeneration; source of regenerating
cells is believed to be satellite cells)
- PERMANENT CELLS: are not capable of regeneration.
As such they remain permanently in the G0 phase. If
there is damage to the cell, other healthy ones cannot
replace it; the damage is permanent. E.g. neurons,
cardiac muscle cells (have no regenerating capacity
beyond early childhood; injured cells r replaced by
scar tissue).
BY CHINEDU HENRY DURU (UNILORIN,
NIGERIA)
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