Male Reproduction

I.	Function of the Male

	1.	Formation of Sperm
	2.	Deposition of Sperm into the Female

II.	Male Reproductive Organs

	1.	Testis
		A.	Produce Spermatozoa
			a.	Develop in Seminiferous tubules
			b.	Sertoli cells act as "Nurse Cells"
		B.	Produce Male Sex Hormones
			a.	Androgens
			b.	Produced in Leydig Cells
	2.	Scrotum
		A.	Temperature Regulation
			a.	Testis located outside body cavity
				i	Sperm can't be produced at body 
					temperature
			b.	Brought closer to body wall when cold
	3.	Epididymis
		A.	Sperm Maturation (Become Motile)
		B.	Sperm Storage
	4.	Vas Deferens (Ductus Deferens)
		A.	Sperm Transport
		B.	Some Storage
	5.	Accessory Sex Glands
		A.	Seminal Vesicles, Prostate, Bulbourethral glands
		B.	Functions:
			a.	Add Fluid (Seminal Plasma) to Semen
			b.	Provide Nutrition to Sperm
			c.	Lubricant
	6.	Urethra
		A.	Sperm Transporter
	7.	Penis
		A.	Copulatory Organ
		B.	Must be rigid and erect to penetrate female
		C.	Blood flows into spongy, cavernous connective 
			tissue chambers
			a.	Corpus Cavernosum
			b.	Corpus Spongiosum
	8.	Prepuce
		A.	Invaginated folds of skin that surround the free 
			extremity of the penis
		B.	Foreskin

III.	Spermatogenesis

	1.	The process involved in the transformation of germinal 
		epithelial cells (stem cells) to spermatozoa

		
	2.	Mitosis and Meiosis occur progressively during 
		spermatogenesis	

		A.	Phases of Sperm precursors
			a.	Spermatogonia
				i.	Undergo mitosis
			b.	Spermatocytes
				i.	Undergo meiosis
				ii.	Spermatocytogenesis is the process 
					in which male germ cells undergo 
					both mitotic and meiotic division: 
					Spermatogonia through Spermatocyte
			c.	Spermatids
				i.	Product of 2nd meiotic division
			d.	Spermatozoa
				i.	Differentiate from Spermatids
				ii.	Spermiogenesis in the metamorphoses 
					from Spermatids to Spermatozoa

	3.	Spermatogenic Wave
		
		A.	Sperm cell division (cycles) occurs over a certain 
			time frame
			
			a.	Species differences
				i.	Boar		 9 days
				ii.	Ram		10 days
				iii.	Stallion	12 days
				iv.	Bull		14 days
			b.	4 or 5 cycles are needed from spermatogonia 
				to spermatozoa
				i.	Bull = 64 days

		B.	Different parts of the seminiferous tubules are at 
			different stages of spermatogenesis at a given time 
			= Spermatogenic Wave
			a.   	This allows sperm to be constantly produced

	4.	Spermatozoa Structure

		A.	Head
			a.	Acrosomal Cap
			b.	Postacrosomal Region
		B.	Tail
			a.	Neck
			b.	Middle Piece
			c.	Annulus
			d.	Principle Piece
			e.	End Piece
		C.	Different species sperm is different
			a.	Size and Shape

IV.	Hormonal Control of Spermatogenesis and Masculinity
	
	1.	Leydig and Sertoli cells are the endocrine cells of the 
		testis
	2.	Gonadotropins
		A.	Luteinizing hormone (LH) and Follicle Stimulating 
			Hormone (FSH)
			are released from the Anterior Pituitary
		B.	LH 
			a.	Stimulate Leydig cells
			b.	Testosterone Production
			c.	Required continuously for spermatogenesis
		C.	FSH
			a.	Stimulates Sertoli Cells
			b.	Androgen Binding Protein Production
				i.	Modulates Androgen Function
			c.	Also secretes some estrogen and inhibin
			d.	FSH is required for initiation of 
				spermatogenesis
				i.	Puberty
				ii.	Physiological or pathological 
					interruption
		D.	FSH and LH are stimulated by Gonadotropin Releasing 
			Hormone (GnRH) released from the Hypothalamus
	3.	Androgens
		A.	Testosterone
			a.	Maintains spermatogenesis
				i.	Supports meiosis
			b.	Causes differentiation of the fetal male 
				reproductive tract 
				and testicular descent
			c.	Maintains Libido (Sex drive)
			d.	Maintains secretory activity of the 
				accessory glands
			e.	Maintains secondary male sexual 
				characteristics
				i.	Heavier bones
				ii.	Greater Muscling
				iii.	Thicker Skin
				iv.	Deeper Voice (Especially bull)        
		B.	Dihydroxytestosterone (DHT)
			a.	Testosterone is converted DHT in androgen 
				sensitive cells
			b.	DHT is the actual steroid that binds to 
				the androgen receptor to elicit and action
		C.	C-16 unsaturated androgens
			a.	Primarily in the Boar
			b.	Acts as a Pheromone in Saliva and Urine
			c.	Responsible for Boar Taint
		
	4.	Negative feedback mechanisms

		A.	Androgens
			a.	Feedback on hypothalamus and pituitary to 
				decrease FSH and LH production
		B.	Inhibin
			a.	Produced by Sertoli cells
			b.	Feedback on pituitary to decrease FSH only

V.	Physical Function of the Male	

	1.	Erection
		A.	An increase in turgidity of the penis
		B.	Sexual Stimulation
			a.	Parasympathetic signal
			b.	Vasodilation of arteries supplying
				cavernous bodies
			c.	Smooth muscle pumps blood corpus cavernosum
				--causes stiffening & straightening
 
	2.	Mounting and Intromission

		A.	Mounting
			a.	Male detects female in estrus 
				(sexual receptivity)
			b.	Must have good footing

		B.	Intromission--Insertion of Penis in Vagina

			a.	Bull
				i.	Lasts 2 seconds
				ii.	Penis spirals at ejaculation

			b.	Boar
				i.	Last up to 7 minutes
				ii.	Spiraled penile end, becomes more 							Corkscrewed during intromission

			c.	Stallion
				i.	Lasts for several minutes
				ii.	No Spiraling

			d.	Ram
				i.	Short intromission
				ii.	Urethral Process disperses semen at 
					ejaculation


	3.	Emission and Ejaculation

		A.	Emission
			a.	Movement of spermatic fluid along 
				vas deferens and pelvic urethra
			b.	Mixes with accessory gland fluids
			c.	Brought about by smooth muscles under ANS 
				(sympathetic) control.

		B.	Ejaculation
			a.	Passage of semen along penile urethra.
			b.	Smooth muscle compresses penile blood to 
				increase blood pressure along 
				corpus spongiosum in a wave-like manner.
			c.	Wave action along urethra causes 								transport of ejaculate.