Cardiovascular Parameters

Tissue Blood Flow

The preparation of the cremaster muscle requires minimal surgery. Even so, the surgery can result in a disruption of the normal blood flow. Several studies have measured

Table I Cremaster Muscle Tissue Blood Flow.


Dissected tissue blood flow ml/min/100g

Intact tissue blood flow ml/min/100g



10 ± 2

9 ± 2

Morff and Granger 1980 [5]

43 ± 3

24 ± 7

Proctor and Busija 1985 [6]


7.7 ± 2.3

3.3 ± 0.5

Klitzman and Duling 1979 [7]

total cremaster blood flow for rats and hamsters using radioactive microspheres in both the surgically dissected tissue and the contralateral undisturbed cremaster muscle (Table I). Blood flow in the dissected cremaster muscle was similar to flow in the intact cremaster and similar to flow in the biceps and gastrocnemius muscles [5]. Other studies reported higher values in the dissected cremaster muscle compared to the undisturbed contralateral muscle. From these studies, it appears that surgery results in an elevated blood flow in the cremaster, although the increased blood flow may be limited to the outside areas exposed to surgical trauma (Table I). At the current time, no measurements of blood flow in the mouse cremaster muscle have been made.

Microvascular Parameters

The range of diameters of arterioles and venules are presented in the Table II. The size of each vessel will vary with the age and size of the animal. The most common method for identifying vessels is based on the feed vessel being classified as first order, and each branching vessel with a decreasing size results in an increase in order number. There are varying numbers of arterioles before capillaries, but there are at least four branching orders of arterioles before the capillaries. The terminal arterioles are located before the capillaries and because of their small size, regulate flow through the capillaries. The arterial vessels supplying the cremaster provide significant resistance such that the pressure in the first-order arterioles averages 40 percent of the systemic pressure. Arteriolar diameter, red cell velocity, and calculated blood flow for representative vessels are presented in Table III.

Essentials of Human Physiology

Essentials of Human Physiology

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