Circulatory System: Cockroach | Additional Study Material for NEET PDF Download

BLOOD VASCULAR SYSTEM

(a) "Open types" or "lacunar types" blood filled in blood sinuses.

(b) True blood vessel - absent

(c) largest blood sinus - "haemocoel"

Blood corpuscles (haematocytes)

(e) "Haematocytes" -

(1) Phagocytosis of bacteria

(2) related with blood clotting.

(f) Blood -

(A) not related with respiration, because respiratory pigment absent.

(B) It works as "hydrolic skeleton ".

(C) Exchange of food, hormones and excretory materials.

two horizontal septa -

(1) Dorsal diaphragm

(2) Ventral diaphragm - these have pores called "fenestrae"

Diaphragms divides the haemocoel in three chambers i.e.

(1) P.C.S. have heart in dorsal part (Peri cardial sinus)

(2) Middle sinus - P. Visceral sinus has alimentary canal and fat body.

(3) Ventral chamber - Perineural sinus has nerve cord.

Heart of Cockroach :-

(a) divided in to 13 chamber

(b) chamber - inverted funnel like

(c) each chamber connected with P.C.S. by 1-pair of pores, called "Ostia". These pores act as valve.

(d) Blood enters from P.C. Sinus to heart through Ostia.

(e) Each Posterior chamber of heart connected/related with anterior chamber by a valve like pore.

(f) These pore help in flow of blood from posterior to anterior part.

(g) two layer of heart wall

outer layer → fibrous connective tissue

Inner layer → muscular

(h) special type of cells attached with heart wall called "nephrocytes". Functions of nephrocytes.

(i) these controlheart beat.

Heart Beat - 49 heartbeat / mintue

(ii) "storage excretion" storage of excretory substance in the form of "Uric acid.:-

First chamber of heart in the form of long tubule called "anterior aorta" It opens into head sinus.

(j) Beside anterior aorta:- One blood vessel each arises from heart in mesothorax and 3-6 abdominal segments.

(k) These are not true blood vessels because

(a) These are not divided into capillaries

(b) open ends.

(l) 13-pair fan like muscles present in P.C.S. called alary muscles. One end which, is pointed is attached to tergum and other end is broad - connected to dorsal diaphragm. These also fused with heart wall these help in "blood circulation".

(m) Tergosternal muscle also help in blood circulation mainly these concerned with respiration.

(n) "Pulsatile ampulla" present at base of each antennae and base of each wing. pulsatile ampulla helps in blood circulation in antennae and wings.

Passage for blood circulation :-

(a) Diastole phase : From P.V.S. blood goes to paricardial sinus and then by ostia blood enter into heart.

(b) Systole phase - when the heart is filled, it contracts from behind to forward and blood enters in head sinus by anterior aorta.

From head sinus →In neck →"P.N. Sinus" oesophagous prevents flow of blood into P.V. sinus two path of blood flow from P.N.S. to P.V.S. -

(a) By fenestrae

(b) through legs

A vertical septa present in cavity of legs, these septa divide cavity of legs in two chamber:-

Dorsal chamber → Connected with p. visceral sinus

Ventral Chamber → Connected with p. neural sinus