skin,fascia,vessels,lymphatics,nervous system,Dr.sabreen mahmoud

1. Skin & fascia & vessels
& nervous system
Dr. Sabreen Mahmoud
Lecturer of human anatomy

2. O B J E C T I V E S
 This lecture introduces some of the basic
structures that compose the body, such as
skin, fascia, vessels and nervous system.
 Without these structures , it is impossible
to describe the composition of the body.

3.  Appreciate the general organization of the
peripheral and central nervous systems.
 Describe the organization of the
cardiovascular system.
 Describe the formation of lymph and its
drainage into the venous system.

4. Skin
Functions of skin:
1. Protection:
2. Prevent dehydration:
3. Sensation:
4. Heat regulation:
5. Excretion:

5. Types of skin:
Thick skin: → palm of the hand &
sole of the foot.
Thin skin: → elsewhere in the body.

6. Skin colour
depends on :
1. Melanin: → brown pigment.
2. Carotene: → yellow pigment.
3. Hemoglobin: → purple color.

7. Skin is formed of 2 parts:
1.Epidermis: Superficial → epithelial
layers, avascular.
2.Dermis: Deep → connective tissue rich
in glands, blood vessels, nerves.

9. Skin appendages
1. Hair
2. Nail
3. Sweat glands: = sudoriferous glands, produce sweat. They are
distributed all over the skin, except lips, glans and nail bed.
4. Sebaceous glands: secrete an oily secretion = sebum. They
are distributed all over the dermis of skin, except for the palms
and soles.
They are abundant in the scalp and face.

10. Fascia
I- Superficial fascia = a general coating of
the body beneath the skin
 loose areolar tissue.
 It determines the shape of the body.

11. Distribution of Fat
 Fat is abundant in gluteal region
(buttocks), front of the thighs, anterior
abdominal wall, mammary gland.
 In females, fat is more abundant.
 Fat is absent from eyelids, external ear,
penis, and scrotum.

12. Features of Superficial Fascia:
very thin on the dorsal aspect of the hands and feet
It is very dense in the scalp, palms, and soles.
It contains:
1. Subcautanous muscles in the face.
2. Mammary gland
3. Lymph nodes
4. Nerves and vessels

13. Function
1. Facilitates movements of the skin.
2. Passage of nerves and vessels to the
skin.
3. conserves body heat.

14. Deep Fascia:
 = fibrous connective tissue that
surrounds the muscles, bones.
 It is devoid of fat, inelastic and tough.

15. Distribution
 best defined in limbs.
 ill-defined on the trunk and face

16. Important Features
1. Extensions → intramuscular septa &
Sheaths for vessels and nerves.
2. Thickenings → Retinacula.

18. Function
1. Keeps the underlying structures in position.
2. muscular attachment
3. venous and lymphatic return.

19. Blood vessels
1. Arteries
2. capillaries & sinusoids
3. veins
4. Arterio-venous connections.

22. 1. Arteries
 carry oxygenated blood,
away from the heart
 deeply situated
 thick-walled,
 highly muscular
 narrow lumen
 Valves are absent
 reddish in color
 movement of blood giving
pulse
 empty up at the time of
death
 If injured, blood comes out
like a ‘fountain’

24. Types of Arteries:
1. Large arteries = (elastic): →aorta.
2. Medium sized = (muscular): → distribute
blood.
3. Arterioles: = the smallest arteries.

25. Arterial anastomosis
 Union between arteries.
 End arteries: arteries with no anastomosis.
Ex: in brain and spinal cord, kidney, spleen.
 When end arteries are completely occluded,
local death result.

26. II- Capillaries
 Microscopic blood vesaels.
 Wall is very thin.
 Arterioles break into the capillaries.
 Form networks and unite to give small veins (
venules).
 Function : exchange of substances (oxygen,
glucose,.......)

28. Blood sinusoids:
 Larger than capillaries.
 Sites: bone marrow,.liver, spleen,...
 Lined by macrophage.

29. III-Veins
 carry deoxygenated blood,
towards the heart
 superficial and deep in
location
 thin-walled
 wide lumen
 Valves are present
 bluish in color
 sluggish movement of blood
 Blood in veins moves under
very low pressure
 Veins get filled up at time of
death
 If injured, blood comes out,
collects in a small area

30. Factors Helping in Venous Return:
 Overflow from the capillaries.
 Negative intra-thoracic pressure.
 Arterial pulsations .
 Venous valves.
 Muscular contractions
Ex: (soleus) known as the peripheral heart.

31. Ill- Arterio-venous anastomoses.
connections between arterioles and venules.
Sites: tips of fingers, tip of nose, ear pinna.
Function : conserve body temperature.

32. LYMPHATIC SYSTEM
3 components:
1) Lymph vessels:
2) lymphoid tissue: lymph nodes, spleen, thymus.
3) Free cells: lymphocytes and phagocytes.

34. Circulation of lymph:
 Lymph is the body fluid which circulates in the lymph vessels.
 clear, colourless and rich in protein.
 Its circulation begins in the tissue spaces → lymphatic
capillaries. → lymph nodes → venous blood stream.
 Lymph carries micro-organisms from the tissue fluid.

35. Video

36. Lymph vessels:
fine capillaries in the tissue spaces → unite together → larger vessels
→ lymph nodes → lymphatic ducts → large veins in the root of the
neck.
The lymphatic capillaries differ from blood capillaries in the
following:
1) Lymphatics have free blind ends.
2) Lymphatic capillaries have greater calibers and are irregular.
3) Lymphatics have wide pores.

37.  Lymphatic vessels and lymphatic ducts → valves →
flow of lymph in one direction.
 In the wall of the intestine → called lacteals.
 This lymph (rich in fat) is milk-white = chyle
 the carrying lymph vessels = lacteals
 (lacteus = milky)

38. The lymphatic vessels
1. Afferent lymphatics
2. Efferent lymphatics:
 At the root of the neck → 2 large lymphatic ducts →
collect the lymph → large veins.
 These are the thoracic duct on the left side & the
right lymphatic duct on the right side

40. Lymphatic vessels are absent in
1) Brain and spinal cord
2) Avascular structures such as the epidermis
of the skin, cartilage, cornea, hair and nails.
3) Bone marrow.
4) Splenic pulp.

41. The flow of lymph is influenced by
1) Contraction of muscles and pulsations
of arteries.
2) Peristaltlc movements of the intestine.
3) Negative intrathoracic pressure.

42. LYMPH NODES:
 oval or kidney-shaped bodies along the
course of lymph vessels.
 present in groups.
1) At the roots of the upper and lower limbs,
i.e. in the axilla and the groin, respectively.
2) Close to the trachea and its bronchi.

45. Functions
1) they are sites where microorganisms are
exposed to phagocytic action by the
macrophages.
2) Lymphocyte production.

46. Lymphocytes:
1) B-lymphocytes: → bone marrow, →
synthesizing antibodies.
2) T-lymphocytes: → in the thymus (thus called
T-type), and they are direct killers.

47. Reticulo-endothelial cells:
 phagocytic properties,
 In the lymph nodes, spleen, the macrophages are of the fixed type.
 macrophages may be present at sites other than the lymphatic
tissue:-
1) In the liver: = Kupffer cells.
2) In the alveoli of the lung: = dust cells.
3) In the blood: = monocytes.

48. Nervous system
(1) Central nervous system (C.N.S.): brain and spinal
cord.
(2) Peripheral nervous system: peripheral nerves.
 12 pairs of cranial nerves
 31 pairs of spinal nerves
 autonomic nerves

50. Structure of the neuron:
 The basic structural unit of the nervous
system is the neuron.
 The neuron consists of a nerve cell and all its
processes.
 dendrites are multiple
 an axon which is single, long.

52. Neurons are classified, into 3 types:
1) Motor neurons: → skeletal muscles.
2) Sensory neurons: → carry impulses → to the C.N.S.
3) Autonomic neurons: → stimulate exocrine glands to
secrete or smooth muscles to contract.

53. Brain
PARTS OF THE BRAIN:
cerebrum, cerebellum and brain stem.
The brain stem comprises 3 parts:
midbrain, pons, and medulla oblongata

54. Ventricles of the brain
 Cavities = ventricles filled with
cerebro-spinal fluid (C.S.F.).
 C.S.F. circulates inside these
ventricles & absorbed in the venous
system.

56. Cranial Nerves:
There are 12 pairs
a) Nerves attached to the cerebrum :
* Olfactory nerve (1st cranial).
* Optic nerve (2nd cranial).
b) Nerves attached to the midbrain:
* Ocular nerve (3rd cranial).
* Trochlear nerve (4th cranial).

58. c) Nerves attached to the pons:
* Trigeminal nerve (5th cranial).
* Abducent nerve (6th cranial).
* Facial nerve (7th cranial).
* Auditory nerve (8th cranial).

59. d) Nerves attached to the medulla oblongata:
* Glossopharyngeal nerve (9th cranial).
* Vagus nerve (10th cranial).
* Accessory nerve (11th cranial).
* Hypoglossal nerve (12th cranial).

60. Spinal cord
The spinal cord lies in the upper 2/3 of the vertebral canal,
extending down to the level of the disc between the 1s and
2nd lumbar vertebrae.
* The spinal cord is composed of spinal segments,
* The grey matter of the cord is H-shaped,
* The cord has a central canal.

62. A lateral horn is present only in the region
from T. 1 to L. 2, and in the sacral region
corresponding to S. 2, 3, 4.
(T. = thoracic ; L. = lumbar; S. = sacral).

63. The function of the nerve cells :
1) Anterior horn: motor.
2) Posterior horn: sensory.
3) Lateral horn: autonomic (sympathetic or
parasyrripathetic).

64. Anatomy of spinal nerve:
31 pairs of spinal nerves :
8 cervical nerves:
12 thoracic nerves:
5 lumbar nerves:
5 sacral
1 coccygeal nerve
Each spinal nerve arises by 2 roots: one dorsal and one
ventral.

67. 1) Dorsal root:
sensory or afferent.
- It has a ganglion = dorsal root ganglion.

68. 2) Ventral root:
motor or efferent.
- Its fibers arise from the anterior horn cells (A.H.Cs ).
- Its fibers also include the preganglionic autonomic.
* The dorsal and ventral roots join each other to form the trunk of the
spinal nerve.
the trunk divides into 2 primary rami (anterior and posterior)

69. 1) Anterior primary ramus:
- form plexuses.
- A sympathetic ganglion is attached to the
anterior primary ramus by (one white ramus
which is myelinated and one grey ramus which
is nonmyelinated).

70. 2) Posterior primary ramus:
It supply the muscles and skin of the back.

71.  DERMATOMES:
Each strip of skin is supplied by spinal nerve,
 GANGLIA:
a collection of nerve cells situated outside the central
nervous system.
 Nucleus: a collection of nerve cells present inside the C.N.S.

72. Classification:
1) Sensory ganglia: attached to the dorsal
roots of spinal nerves = dorsal root ganglia.
2) Autonomic ganglia: sympathetic
ganglia & parasympathetic ganglia

73. Rami of sympathetic ganglia:
1) White ramus communicans: is
myelinated = preganglionic.
2) Grey ramus communicans: is non-
myelinated = postganglionic.

74. Autonomic nervous system
1) The sympathetic →stress and strain (as
in fight and flight).
2) The parasympathetic part → rest and
relaxation (as in sleep).

76. (autonomic = self-controlling).
Its higher center is represented by the
hypothalamus.

77. The sympathetic ganglia are situated
close to the vertebral column,
the parasympathetic ganglia are
embedded in the walls of viscera.

78. Distribution of sympathetic fibres:
1) The preganglionic sympathetic fibres :
a - relay in ganglia in the sympathetic trunks.
b - relay in the medulla of the suprarenal
gland.

79. 2) The postganglionic sympathetic fibres
a - To exocrine glands.
b- To walls of viscera.
c - To heart.
d - To blood vessels (vasomotor).
e-To skin (motor).

80. Meninges
1) Dura mater:
2) Arachnoid mater:
3) Pia mater:

82. The 3 meninges are separated
1) Epidural space:
2) Subdural space:
3)Subarachnoid space: contains the C.S.F &
blood vessels.

85. Thanks
Dr. Sabreen